Area ratios of patterned coatings on rf electrodes to reduce sticking

ABSTRACT

An electrosurgical system includes an RF current generator, a handle body, and an end effector. The end effector may include a first and a second energy delivery surface. At least a portion of either first or second energy delivery surfaces, or both, may include one or more patterned coatings of an electrically non-conducting non-stick material. The material may be deposited on a surface of, within a depression in, or on features extending from the energy surfaces, or through an overmolding process. The patterned coating may be formed from a coating of the material from which portions have been removed. An energy delivery surface has a first area, and the patterned coating has a second area. A ratio of the second area to the first area may be less than or equal to about 0.9, less than or equal to about 0.7, or less than or equal to about 0.5.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application claiming priority under35 U.S.C. § 120 to U.S. patent application Ser. No. 15/476,665, entitledAREA RATIOS OF PATTERNED COATINGS ON RF ELECTRODES TO REDUCE STICKING,filed Mar. 31, 2017, now U.S. Patent Application Publication No.2018/0280075, the entire disclosure of which is hereby incorporated byreference herein.

BACKGROUND

Electrosurgical devices are used in many surgical operations.Electrosurgical devices apply electrical energy to tissue in order totreat tissue. An electrosurgical device may comprise an instrumenthaving a distally-mounted end effector comprising one or moreelectrodes. The end effector can be positioned against tissue such thatelectrical current is introduced into the tissue. Electrosurgicaldevices can be configured for bipolar operation. During bipolaroperation, current is introduced into and returned from the tissue byactive and return electrodes, respectively, of the end effector. Bipolardevices may also have an end effector consisting of two or more jawseach having at least one of the active and or return electrodes. Atleast one of the jaws is moveable from a position spaced apart from theopposing jaw for receiving tissues to a position in which the spacebetween the jaws is less than that of the first position. Movement ofthe moveable jaw compresses the tissue held between. Heat generated bythe current flow through the tissue in combination with the compressionachieved by the jaw movement may form hemostatic seals within the tissueand/or between tissues and thus may be particularly useful for sealingblood vessels, for example. The end effector of an electrosurgicaldevice sometimes also comprises a cutting member that is movablerelative to the tissue and the electrodes to transect the tissue.

Electrosurgical devices also may include mechanisms to clamp tissuetogether, such as a stapling device, and/or mechanisms to sever tissue,such as a tissue knife. The electrosurgical device may also include anultrasonic vibrating blade. An electrosurgical device may include ashaft for placing the end effector proximate to tissue undergoingtreatment. The shaft may be straight or curved, bendable ornon-bendable. In an electrosurgical device including a straight andbendable shaft, the shaft may have one or more articulation joints topermit controlled bending of the shaft. Such joints may permit a user ofthe electrosurgical device to place the end effector in contact withtissue at an angle to the shaft when the tissue being treated is notreadily accessible using an electrosurgical device having a straight,non-bending shaft.

Electrical energy applied by an electrosurgical device can betransmitted to the instrument by a generator. The electrical energy maybe in the form of radio frequency (“RF”) energy. The electrical energymay be in the form of radio frequency (“RF”) energy that may be in afrequency range described in EN 60601-2-2:2009+A11:2011, Definition201.3.218—HIGH FREQUENCY. For example, the frequency in monopolar RFapplications is typically restricted to less than 5 MHz. However, inbipolar RF applications, the frequency can be almost anything.Frequencies above 200 kHz can be typically used for monopolarapplications in order to avoid the unwanted stimulation of nerves andmuscles which would result from the use of low frequency current. Lowerfrequencies may be used for bipolar techniques if the risk analysisshows the possibility of neuromuscular stimulation has been mitigated toan acceptable level. Normally, frequencies above 5 MHz are not used inorder to minimize the problems associated with high frequency leakagecurrents. However, higher frequencies may be used in the case of bipolartechniques.

During its operation, an electrosurgical device can transmit RF energythrough tissue compressed between the two or more jaws. Such RF energymay cause ionic agitation in the tissue, in effect producing resistive(joule) heating, and thereby increasing the temperature of the tissue.The temperatures involved during the sealing process may lead to tissuesticking to a stainless steel electrode. RF energy may work particularlywell on connective and vascular tissue, which primarily comprisecollagen and elastin that liquefies when heated and reforms into a fusedmass when it cools. Because a distinct thermal spread boundary may becreated between the affected tissue and the surrounding tissue, surgeonscan operate with a high level of precision and control, withoutsacrificing un-targeted adjacent tissue. In many surgical procedures, RFenergy may be useful for sealing blood vessels.

During surgical resection of tissue, blood vessels may be severed eitheras part of the procedure or ancillary to the resection of a tissue ofinterest. Once a blood vessel has been severed, blood may flow into thesurgical site, potentially obscuring the site from view and renderingthe surgical procedure more difficult. If the severed blood vessel is amajor vessel, such as an artery or vein, the patient may suffersignificant blood loss during the procedure thereby significantlycompromising the patient's health.

It may be understood that successful electrosurgery-based sealing of ablood vessel requires the application of a sufficient compressive forceto close the blood vessel, a consistent gap between electrodes, and theapplication of the RF energy to heat and seal the tissue undercompression. In order to apply the sufficient compressive force to theblood vessel, the end effector jaws of the electrosurgical device mustsecurely grasp the blood vessel and apply sufficient pressure toapproximate the vessel's walls to a precise gap while the sealingprocess occurs.

It may be recognized that the application of the RF energy to heat andseal the tissue under compression may lead to changes in the tissuecomposition which may include charring or the forming of a coagulum fromthe heated tissue. The charred tissue or coagulum may adhere to one ormore of the jaws of the end effector making it difficult to separate thesealed tissue from the end effector. In some circumstances, an attemptto manually separate the charred tissue or coagulum from the one or morejaws may result in a breach of the tissue seal, thereby permittingbleeding in the surgical site. Therefore, it may be useful to design anend effector of an electrosurgical device with components capable ofallowing easy release of the sealed tissue from the one or more endeffector jaws.

SUMMARY

In one aspect, an electrosurgical system may include an RF currentgenerator, a handle body, and an end effector in mechanicalcommunication with the handle body, in which the end effector mayinclude a first jaw comprising a first energy delivery surface inelectrical communication with a first terminal of the RF currentgenerator, and a second jaw including a second energy delivery surfacein electrical communication with a second terminal of the RF currentgenerator, in which at least a portion of the first energy deliverysurface includes a patterned coating of an electrically non-conductingnon-stick material.

In one aspect of the electrosurgical system, the first energy deliverysurface has a first area and the at least portion of the first energydelivery surface comprising the patterned coating has a second area.

In one aspect of the electrosurgical system, a ratio of the second areato the first area is less than or equal to about 0.9.

In one aspect of the electrosurgical system, a ratio of the second areato the first area is less than or equal to about 0.7.

In one aspect of the electrosurgical system, a ratio of the second areato the first area is less than or equal to about 0.5.

In one aspect of the electrosurgical system, the electricallynon-conducting non-stick material has a surface energy value between1100 mJ/m² and 5 mJ/m².

In one aspect of the electrosurgical system, the electricallynon-conducting non-stick material has a surface energy value between 50mJ/m² and 40 mJ/m².

In one aspect of the electrosurgical system, the electricallynon-conducting non-stick material has a surface energy value between 40mJ/m² and 12 mJ/m².

In one aspect, an end effector for an electrosurgical device may includea first jaw having a first energy delivery surface configured to be inelectrical communication with a first terminal of an RF currentgenerator, and a second jaw having a second energy delivery surfaceconfigured to be in electrical communication with a second terminal ofthe RF current generator, in which at least a portion of the firstenergy delivery surface includes a patterned coating of an electricallynon-conducting non-stick material.

In one aspect of the end effector, the first energy delivery surface hasa first area and the at least portion of the first energy deliverysurface comprising the patterned coating has a second area.

In one aspect of the end effector, a ratio of the second area to thefirst area is less than or equal to about 0.8.

In one aspect of the end effector, a ratio of the second area to thefirst area is less than or equal to about 0.7.

In one aspect of the end effector, a ratio of the second area to thefirst area is less than or equal to about 0.5.

In one aspect of the end effector, the electrically non-conductingnon-stick material has a surface energy value between 1100 mJ/m² and 5mJ/m².

In one aspect of the end effector, the electrically non-conductingnon-stick material has a surface energy value between 50 mJ/m² and 40mJ/m².

In one aspect of the end effector, the electrically non-conductingnon-stick material has a surface energy value between 40 mJ/m² and 12mJ/m².

In one aspect of the end effector, the patterned coating includes theelectrically non-conducting non-stick material disposed within one ormore recessed features fabricated in the first energy delivery surface.

In one aspect of the end effector, the one or more recessed featuresinclude one or more circular features.

In one aspect of the end effector, the one or more recessed featuresinclude one or more rectangular features.

In one aspect of the end effector, the one or more recessed featuresinclude one or more linear features.

In one aspect of the end effector, the one or more linear features aredisposed along or parallel to a longitudinal axis of the first energydelivery surface.

In one aspect of the end effector, the one or more linear features aredisposed along or parallel to a transverse axis of the first energydelivery surface.

In one aspect of the end effector, the patterned coating includes theelectrically non-conducting non-stick material disposed on and in directphysical communication with an exposed surface of the first energydelivery surface.

In one aspect of the end effector, the patterned coating includes acoating of the non-stick material lacking one or more portions of thenon-stick material.

In one aspect of the end effector, the portions of the non-stickmaterial include one or more circular portions of the non-stickmaterial.

In one aspect of the end effector, the portions of the non-stickmaterial include one or more rectangular portions of the non-stickmaterial.

In one aspect of the end effector, the portions of the non-stickmaterial include one or more elongated portions of the non-stickmaterial.

In one aspect of the end effector, at least a portion of the secondenergy delivery surface includes a second patterned coating of theelectrically non-conducting non-stick material that is disposed on andis in direct physical communication with an exposed surface of thesecond energy delivery surface; and in which the patterned coating isspatially offset with respect to the second patterned coating when thefirst jaw is brought into a proximate position to the second jaw.

In one aspect of the end effector, the second energy delivery surfacehas a third area and the at least portion of the second energy deliverysurface comprising the second patterned coating has a fourth area.

In one aspect of the end effector, a ratio of the fourth area to thethird area is less than or equal to about 0.8.

In one aspect of the end effector, a ratio of the fourth area to thethird area is less than or equal to about 0.7.

In one aspect of the end effector, a ratio of the fourth area to thethird area is less than or equal to about 0.6.

In one aspect of the end effector, the patterned coating includes acoating of the non-stick material lacking one or more elongated portionsof the non-stick material and the second patterned coating comprises acoating of the non-stick material lacking one or more second elongatedportions of the non-stick material.

BRIEF DESCRIPTION OF THE FIGURES

The features of the various aspects are set forth with particularity inthe appended claims. The various aspects, however, both as toorganization and methods of operation, together with advantages thereof,may best be understood by reference to the following description, takenin conjunction with the accompanying drawings as follows:

FIG. 1A shows a surgical instrument in electrical communication with anenergy source, according to one aspect of the present disclosure.

FIG. 1B is a detailed view of the end effector of the surgicalinstrument shown in FIG. 1A, according to one aspect of the presentdisclosure.

FIG. 2 illustrates a perspective view of one aspect of a first jaw ofthe end effector of the electrosurgical instrument depicted in FIGS. 1Aand 1B.

FIG. 3 depicts a first aspect of a surface of a first jaw of the endeffector of the electrosurgical instrument depicted in FIGS. 1A and 1B.

FIG. 4 depicts a second aspect of a surface of a first jaw of the endeffector of the electrosurgical instrument depicted in FIGS. 1A and 1B.

FIG. 5 depicts a third aspect of a surface of a first jaw of the endeffector of the electrosurgical instrument depicted in FIGS. 1A and 1B.

FIG. 6 depicts a fourth aspect of a surface of a first jaw of the endeffector of the electrosurgical instrument depicted in FIGS. 1A and 1B.

FIG. 7 depicts a fifth aspect of a surface of a first jaw of the endeffector of the electrosurgical instrument depicted in FIGS. 1A and 1B.

FIG. 8 depicts a boxplot of the sticking force of a tissue to a firstjaw of an end effector of the electrosurgical instrument depicted inFIGS. 1A and 1B, wherein the surface of the first jaw may comprise oneof a number of percent coatings of a non-stick material.

FIG. 9 depicts a boxplot of a tissue burst pressure of a tissue sealedby the end effector of the electrosurgical instrument depicted in FIGS.1A and 1B, wherein the surface of the first jaw may comprise one of anumber of percent coatings of a non-stick material.

FIGS. 10A-C depict aspects of a surface of a first jaw of the endeffector of the electrosurgical instrument depicted in FIGS. 1A and 1Bdepicting surface features of the first jaw having a coating of anon-stick material.

FIG. 10D depicts an aspect of a top view of a second jaw of the endeffector of the electrosurgical instrument depicted in FIGS. 1A and 1Bdepicting surface features of the second jaw having a coating of anon-stick material

FIG. 11 depict aspects of a surface of a first jaw of the end effectorof the electrosurgical instrument depicted in FIGS. 1A and 1B in whichthe surface features are illustrated in FIG. 17A of the first jawcomprising a number of percent coatings of a non-stick material.

FIG. 12 depict aspects of a surface of a first jaw of the end effectorof the electrosurgical instrument depicted in FIGS. 1A and 1B in whichthe surface features are illustrated in FIGS. 17C and 17D of the firstjaw comprising a number of percent coatings of a non-stick material.

FIG. 13 depicts a boxplot of the sticking force of a tissue to a firstjaw of an end effector of the electrosurgical instrument depicted inFIGS. 1A and 1B, in which the surface features are illustrated in FIGS.17A-17D of the first jaw comprising a number of percent coatings of anon-stick material.

FIG. 14 depicts a boxplot of the burst pressure of a tissue sealed bythe end effector of the electrosurgical instrument depicted in FIGS. 1Aand 1B, in which the surface features are illustrated in FIGS. 17A-17Dof the first jaw comprising a number of percent coatings of a non-stickmaterial.

FIG. 15 depict a main effects plots, derived from the boxplots depictedin FIG. 13 of the sticking force of a tissue to a first jaw of an endeffector of the electrosurgical instrument depicted in FIGS. 1A and 1B.

FIG. 16 depicts RF current paths through a tissue compressed between afirst and a second electrode in which a surface of the first and thesecond electrode comprises a patterned non-stick coating.

DETAILED DESCRIPTION

The following description of certain examples of the technology shouldnot be used to limit its scope. Other examples, features, aspects,aspects, and advantages of the technology will become apparent to thoseskilled in the art from the following description. As will be realized,the technology described herein is capable of other different andobvious aspects, all without departing from the technology. Accordingly,the drawings and descriptions should be regarded as illustrative innature and not restrictive.

It is further understood that any one or more of the teachings,expressions, aspects, examples, etc. described herein may be combinedwith any one or more of the other teachings, expressions, aspects,examples, etc. that are described herein. The following describedteachings, expressions, aspects, examples, etc. should, therefore, notbe viewed in isolation relative to each other. Various suitable ways inwhich the teachings herein may be combined will be readily apparent tothose of ordinary skill in the art in view of the teachings herein. Suchmodifications and variations are intended to be included within thescope of the claims.

Also, in the following description, it is to be understood that termssuch as front, back, inside, outside, upper, lower, top, bottom and thelike are words of convenience and are not to be construed as limitingterms. Terminology used herein is not meant to be limiting insofar asdevices described herein, or portions thereof, may be attached orutilized in other orientations. The various aspects will be described inmore detail with reference to the drawings. Throughout this disclosure,the term “proximal” is used to describe the side of a component, e.g., ashaft, a handle assembly, etc., closer to a user operating the surgicalinstrument, e.g., a surgeon, and the term “distal” is used to describethe side of the component farther from the user operating the surgicalinstrument.

Aspects of the present disclosure are presented for a singleelectrosurgical device configured for grasping tissue and performingsealing procedures using electrical and/or other energy. An end effectorof the electrosurgical device may include multiple members arranged invarious configurations to collectively perform the aforementionedfunctions. As used herein, an end effector may be referred to as a jawassembly or clamp jaw assembly comprising an upper jaw member and alower jaw member where at least one of the upper jaw member and thelower jaw member may be movable relative to the other. Jaw members maybe adapted to connect to an electrosurgical energy source. A jaw membermay incorporate an electrode. The electrode may be a positive ornegative electrode. In a bipolar electrosurgical device, the electrodesmay be adapted for connection to the opposite terminals of theelectrosurgical energy source, such as a bipolar radio frequency (RF)generator, so as to generate a current flow therebetween. Anelectrosurgical energy may be selectively communicated through tissueheld between the jaw members to effect a tissue seal and/or treatment.Tissue may be coagulated from the current flowing between the oppositepolarity electrodes on a jaw member.

At least one jaw member may include a knife channel defined thereinconfigured to reciprocate a knife therealong for severing tissue heldbetween the jaw members. The knife channel may be an extended slot inthe jaw member. The knife may be provided within a recess associatedwith the at least one jaw member. The electrosurgical device may haveboth coagulation and cutting functions. This may eliminate or reduceinstrument interchange during a surgery. Cutting may be achieved usingmechanical force alone or a combination of mechanical force and theelectrosurgical energy. The electrosurgical energy may be selectivelyused for coagulation and/or cutting. The knife may be made from anelectrically conductive material adapted to connect to theelectrosurgical source, and selectively activatable to separate tissuedisposed between the jaw members. The knife may be spring biased suchthat once tissue is severed, the knife may automatically return to anunengaged position within the knife channel or a retracted position inthe recess.

In some aspects, the jaw members may be movable relative to each other.During operation of the electrosurgical device, at least one of the jawmembers may move from a first, open position where the jaw members canbe disposed around a mass of tissue, to a second, closed position wherethe jaw members grasp the tissue. The jaw members therefore may movethrough a graspers-like range of motion, similar to that of conventionalpliers. In the second position, current flows between the jaw members toachieve hemostasis of the tissue captured therebetween. The jaw membersmay be configured to have a relatively thick proximal portion to resistbending. At least one of the jaw members may have a three-dimensionalconfiguration with a D-shaped cross-sectional. The three-dimensionalconfiguration with the D-shaped cross-sectional may resist bending. Alock mechanism may be included to lock the jaw members in the closedposition. The lock mechanism may set the clamp pressure between the jawmembers. At least one electrically conductive gap setting member may beprovided between the jaw members to establish a desired gap betweenelectrodes in bipolar electrosurgical devices.

The electrosurgical device may incorporate components to set a gapbetween the jaws of the end effector, grasp a tissue via the endeffector, deliver energy to the tissue via one or more electrodes, andcut the tissue via a dissecting device such as a tissue knife. Thestructural capabilities of any aspect of an electrosurgical device maybe designed for use in one or more of a variety of surgical procedures.In some surgical procedures, the treated tissue may be readilyaccessible to an end effector affixed to a relatively straight andunbendable shaft. In some alternative surgical procedures, the tissuemay not be readily accessible to the end effector on such a shaft. Insuch procedures, the electrosurgical device may incorporate a shaftdesigned to bend so that the end effector may contact the tissuerequiring treatment. In such a device, the shaft may include one or morearticulated joints that may permit the shaft to bend under control bythe user. A sliding knife may include a feature to provide actuatingforce to the sliding knife. A knife actuator may be operably coupled tothe shaft for selectively reciprocating the knife through the knifechannel.

A front portion assembly may be designed for a specific surgicalprocedure, while a reusable handle assembly, configured to releasablyattach to a front portion assembly, may be designed to provide controlof surgical functions common to each front portion assembly, such astissue grasping, cauterizing, and cutting. Consequently, the number andtypes of devices required for surgeries can be reduced. The reusablehandle assembly may be designed to automate common functions of theelectrosurgical device. Device intelligence may be provided by acontroller located in the reusable handle assembly that is configured toreceive information from a front portion assembly. Such information mayinclude data regarding the type and use of the front portion assembly.Alternatively, information may include data indicative of the positionand/or activation of control components (such as buttons or slides thatcan be manipulated) that may indicate what system functions should beactivated and in what manner.

In some non-limiting examples, the controller may supply the RF currentwhen the energy activation control is placed in an activating positionby the user. In some alternative non-limiting examples, the controllermay supply the RF current for a predetermined period of time once theenergy activation control is placed in an activing position. In yetanother non-limiting example, the controller may receive data related tothe position of the jaw members and prevent the RF current from beingsupplied to the to the one or more tissue power contacts if the jawmembers are not in a closed position.

In some aspects, any of the mentioned examples also may be configured toarticulate along at least one axis through various means, including, forexample, a series of joints, one or more hinges or flexure bearings, andone or more cam or pulley systems. Other features may include cameras orlights coupled to one or more of the members of the end effector, andvarious energy options for the surgical device.

The electrosurgical device can be configured to source energy in variousforms including, without limitation, electrical energy, monopolar and/orbipolar RF energy, microwave energy, reversible and/or irreversibleelectroporation energy, and/or ultrasonic energy, heat energy, or anycombination thereof, to the tissue of a patient either independently orsimultaneously. The energy can be transmitted to the electrosurgicaldevice by a power source in electrical communication with theelectrosurgical device. The power source may be a generator. The powersource may be connected to the electrosurgical device via a suitabletransmission medium such as a cable. The power source may be separatefrom the electrosurgical device or may be made integrally with theelectrosurgical device to form a unitary electrosurgical system. In onenon-limiting example, the power source may include one or more batterieslocated within a portion of the electrosurgical device. It may beunderstood that the power source may source energy for use on the tissueof the patient as well as for any other electrical use by other devices,including, without limitation, lights, sensors, communication systems,indicators, and displays, which operate in relation to and/or with theelectrosurgical device to form an electrosurgical system.

As disclosed above, the electrosurgical device may be configured tosource electrical energy in the form of RF energy. The electrosurgicaldevice can transmit the RF energy through tissue compressed between twoor more jaw members. In some surgical procedures, RF energy may beuseful for removing, shrinking, or sculpting soft tissue whilesimultaneously sealing blood vessels. RF energy may work particularlywell on connective tissue, which is primarily composed of collagen andshrinks when contacted by heat. Because a sharp boundary may be createdbetween the affected tissue and the surrounding tissue, surgeons canoperate with a high level of precision and control, without sacrificinguntargeted adjacent tissue.

The RF energy may be in a frequency range described in EN60601-2-2:2009+A11:2011, Definition 201.3.218—HIGH FREQUENCY. Forexample, the frequency in monopolar RF applications may be typicallyrestricted to less than 5 MHz. However, in bipolar RF applications, thefrequency can be almost anything. Frequencies above 200 kHz can betypically used for monopolar applications in order to avoid the unwantedstimulation of nerves and muscles that would result from the use of lowfrequency current. Lower frequencies may be used for bipolarapplications if the risk analysis shows the possibility of neuromuscularstimulation has been mitigated to an acceptable level. Normally,frequencies above 5 MHz are not used in order to minimize the problemsassociated with high frequency leakage currents. Higher frequencies may,however, be used in the case of bipolar applications.

As discussed above, the electrosurgical device may be used inconjunction with a generator. The generator may be an electrosurgicalgenerator characterized by a fixed internal impedance and fixedoperating frequency that deliver maximum power to an external load(e.g., tissue) having an electrical impedance in the range of about 1ohm to about 500 ohms. In this type of bipolar electrosurgicalgenerator, the applied voltage may increase monotonically as the loadimpedance increases toward the maximum “open circuit” voltage as theload impedance increases to levels of tens of thousands of ohms or more.In addition, the electrosurgical device may be used with a bipolarelectrosurgical generator having a fixed operating frequency and any oneor more of a substantially constant output voltage, output current, oroutput power over a range of load impedances of tens of ohms to tens ofthousands of ohms including “open circuit” conditions. Theelectrosurgical device may be advantageously used with a bipolarelectrosurgical generator of either a variable voltage design orsubstantially constant voltage design in which the applied voltage maybe interrupted when the delivered current decreases below apredetermined level. Such bipolar generators may be referred to asautomatic generators in that they may sense the completion of thecoagulation process and terminate the application of voltage, oftenaccompanied by an audible indication in the form of a cessation of a“voltage application” tone or the annunciation of a unique “coagulationcomplete” tone. Further, the electrosurgical device may be used with anelectrosurgical generator whose operating frequency may vary with theload impedance as a means to modulate the applied voltage with changesin load impedance.

Various aspects of electrosurgical devices use therapeutic and/orsub-therapeutic electrical energy to treat tissue. Some aspects may beutilized in robotic applications. Some aspects may be adapted for use ina hand operated manner. In one non-limiting example, an electrosurgicaldevice may include a proximal handle, a distal working end or endeffector, and an introducer or elongated shaft disposed in-between.

In some non-limiting medical procedures, the electrosurgical device maybe used to weld or seal vessels prior to tissue resection. Such vesselsalso may be removed as part of procedures to resect other tissue such ascysts, tumors, or infected materials. Blood vessel sealing may reducebleeding, thereby decreasing potential harmful effects during aresection procedure. In such procedures, vessels may be cut at the seallocation. It may be understood that complete sealing may be required atthe site of the cut to prevent bleeding. It is therefore useful to havean electrosurgical device that may be prevented from cutting a vesseluntil complete sealing is assured.

To properly seal vessels, two mechanical parameters that affectthickness of the sealed vessel may be accurately controlled: thepressure applied to the vessel and the gap between the electrodes.Proper sealing may require that sufficient pressure is placed on thevessel to assure that the vessel walls are proximate to each other andno intervening gap remains therebetween. The vessel may be compressed toa pressure within a predetermined range. A typical range of appropriatepressures may be between about 30 pounds per square inch (about 0.2 MPa)and about 250 pounds per square inch (about 1.7 MPa). In somealternative aspects, a range of appropriate pressures may be betweenabout 250 pounds per square inch (about 1.7 MPa) and about 1050 poundsper square inch (about 7.2 MPa). In addition, proper sealing may requirethat sufficient power is provided to assure that the vessel wallsreceive sufficient heat to weld the walls together. Thus, both tissuecompression and sufficient electrosurgery device power may be requiredto form a proper seal. These can be achieved by the jaw members of theend effector. As mentioned above, the jaw members may grasp, compress,and deliver the energy to the tissue.

To effectively carry out hemostasis, the jaw members should efficientlyconduct a proper current flow through the grasped tissue. When thatcurrent is insufficient, coagulation of the tissue or vessel may becompromised. When the current is excessive, correspondingly excessiveheating may occur with a potential for the generation of damagingelectrical arcing. Excessive heating may result in the phenomenon oftissue and blood coagulum sticking to the surface of the jaw members.This may result in increased electrical impedance between the electrodesof the device and the tissue that may subsequently be grasped for thepurpose of treatment. Such sticking tissue may evoke a disruption of thecoagulated surface, which in itself may compromise the intendedhemostatic effect. The end effector may incorporate highly polishedelectrode surfaces for the purpose of reducing the extent of tissuesticking as well as to facilitate their cleaning when sticking doesoccur.

When grasping tissue, the jaw members may come into mutual contact,causing a short circuit. For example, when a small tissue component isgrasped between the jaw members and/or when the jaw members arecompressed hard, the electrodes may be in contact with each other in thevicinity of the grasped tissue, causing short-circuiting. The jawmembers may include insulative coatings that may be in contact in somegeometry.

In various aspects, an electrically conductive gap setting member may beprovided between the jaw members. The electrically conductive gapsetting member may be affixed on and/or integral to one jaw member andextend to the other jaw member. The electrically conductive gap settingmember may protrude through the jaw member. The electrically conductivegap setting member may define a gap between the jaw members. Theelectrically conductive gap setting member may be electricallyconductive. The gap setting member may be made of a material that iselectrically conductive and also is stiff to resist deformation inresponse to an applied force. The electrically conductive gap settingmember may be sized and configured to avoid short-circuiting between theopposing electrodes and/or ensure that the electrodes would not closeenough to arc without the presence of tissue between the electrodes.

In various aspects, the electrodes on the surfaces of the jaw membersmay be made of metal. The exposed portions of the surfaces of the jawmembers may have smooth surfaces to minimize sticking to tissue orcoagulum and to facilitate their cleaning when tissue debris or coagulumdoes accumulate. The surfaces of the jaw members may include thermallyconductive components such as copper, silver, aluminum, tungsten,nickel, or any other thermally conductive materials that may occur tothose skilled in the art. Laminar composites coated with a biocompatiblemetal coating may be applied to the surfaces. The jaw members mayinclude laminar composites of thermally conductive copper and amechanically stronger material, particularly, higher modulus stainlesssteel. Biocompatibility of the jaw members may be maintained through anelectro-deposited biocompatible metal coating, such as chromium, thatcoats both the stainless steel and copper laminate while not affectingthe electrically insulative members. In some non-limiting examples, forend effectors with small jaw members, for example, having a width ofabout 0.039″ (1 mm) at their tip, laminar composites having a layer of304 stainless steel of thickness of about 0.011″ and a correspondinglayer of copper having about 0.052″ thickness may be provided. Forlarger jaw members, laminar composites having a layer of 304 stainlesssteel of thickness about 0.015″ and a corresponding layer of copperhaving about 0.075″ to about 0.085″ thickness may be provided. Thebiocompatible coating may be provided, for example, as anelectro-deposited chromium coating, for example, that identified asMED-COAT 2000 marketed by Electrolyzing Corporation of Ohio, Cleveland,Ohio 44112. This biocompatible coating is described as meeting orexceeding USP Class VI certification.

In various aspects, the length of the jaw members may be set for theparticular application in surgery. For example, the length of the jawmembers of about 0.4″ or 0.5″ to about 0.75″, such as about 0.47″ (12mm), may be used for smaller anatomical structures or fine work. Forlarger anatomical structures, the length of the jaw members may be about1″ or greater, for example, about 1.57″ (40 mm).

As disclosed above, the exposed portions of the surfaces of the jawmembers may have smooth surfaces to minimize sticking to tissue orcoagulum and to facilitate their cleaning when tissue debris or coagulumdoes accumulate. The surfaces of the jaw members may include thermallyconductive components such as copper, silver, aluminum, tungsten,nickel, or any other thermally conductive materials that may occur tothose skilled in the art. Laminar composites coated with a biocompatiblemetal coating may be applied to the surfaces. The jaw members mayinclude laminar composites of thermally conductive copper and amechanically stronger material, particularly, higher modulus stainlesssteel. It may be recognized that tissue or coagulum may neverthelessadhere to the jaw members even for jaw members having smooth surfaces.As a result, it may be difficult to remove the sealed tissue from thejaw members to permit the end effector to be moved from one location toanother. Manual removal of such tissue or coagulum from the jaw membersmay adversely affect the quality of the seal of the tissue produced bythe electrosurgical device.

In some aspects, non-stick metal coatings may comprise coatings that maybe used to reduce or prevent the ability of other materials to stick tometal surface, for example fried eggs to a non-stick material coatedpan. Properties of such non-stick coatings may include a low surfaceenergy value. A surface energy value may be used to quantify thedisruption of intermolecular bonds that occur when a surface is created.The surface energy may therefore be considered as the excess energy atthe surface of a material compared to the bulk, or the work required tobuild an area of a particular surface. Another way to view the surfaceenergy is to relate it to the work required to cut a bulk sample,thereby creating two surfaces. Table 1 presents some exemplary values ofsurface energy for a number of materials.

TABLE 1 Surface Energy of Sample Materials Material Surface Energy(mJ/m²) Copper 1103 Aluminum 840 Zinc 753 Stainless Steel 700-1100Aluminum oxide - sapphire 638 Tin 526 Lead 458 Silicon dioxide - silica287 Glass/Porcelain 250-500  Mica 120 Polyimides 46 Polyvinylchloride 42Aliphatic or Semi-aromatic 41 Polyamides Polystyrene 40 Polyethylene 32Polytetrafluoroethylene 18 Polyhexafluoropropylene 12

For purposes of comparison, stainless steel may typically have a surfaceenergy value of about 700 mJ/m² (dyne/cm) to about 1000 mJ/m² (dyne/cm)which promotes low adhesion (low adhesion results in lower sticking).Non-stick materials, however, may have surface energy values of about 50mJ/m² to about 40 mJ/m². Non-limiting examples of such surface energyvalues for non-stick materials may include values of about 50 mJ/m²,about 48 mJ/m², about 46 mJ/m², about 44 mJ/m², about 42 mJ/m², about 40mJ/m², and any value or range of values therebetween includingendpoints. Such non-stick materials may include common polymers, such asaliphatic or semi-aromatic polyamides (for example Nylon) and polyimides(for example, Kapton®). It may be recognized that the surface energyvalues of such polymers are much lower than that of, for example,stainless steel, and thus may be less prone to sticking. Othermaterials, having even lower surface energy values—for example, in therange of about 40 mJ/m² to about 12 mJ/m²—may be even more resistant tosticking. Non-limiting examples of such surface energy values fornon-stick materials may include values of about 40 mJ/m², about 36mJ/m², about 32 mJ/m², about 28 mJ/m², about 24 mJ/m², about 20 mJ/m²,about 16 mJ/m², about 12 mJ/m², and any value or range of valuestherebetween including endpoints. Polytetrafluoroethylene (PTFE) is onesuch material, having a surface energy of about 18 mJ/m². Still othermaterials may have even lower values of surface free energy, such asthose materials having surface micro- and/or nano-structures that maytake advantage of the “lotus leaf effect.” The surface free energy ofsuch materials, natural or man-made, may have a value of about 5 mJ/m².In some non-limiting aspects, therefore, a non-stick material may be onehaving a non-zero, positive-valued surface energy less than that ofstainless steel. For example, a non-stick material may have a surfaceenergy of less than about 1100 mJ/m² to about 5 mJ/m². Thus, in somegeneral non-limiting examples, such surface energy values of a non-stickmaterial may include values of about 1100 mJ/m², about 1000 mJ/m², about900 mJ/m², about 800 mJ/m², about 700 mJ/m², about 600 mJ/m², about 500mJ/m², about 400 mJ/m², about 300 mJ/m², about 200 mJ/m², about 100mJ/m², about 50 mJ/m², about 40 mJ/m², about 30 mJ/m², about 20 mJ/m²,about 10 mJ/m², about 5 mJ/m², and any value or range of valuestherebetween including endpoints.

Such non-stick coatings may be electrically conductive ornon-conductive. Electrically conductive non-stick coatings may besufficiently conducting to permit electrical current to pass into thetissue contacted by jaws of an electrosurgical device to effectlocalized heating and tissue sealing. However, portions of jaw memberscoated with an electrically non-conductive coating will not permitelectrical current to pass into the tissue. It may be suspected that anamount of adhesive (sticking) force of a tissue to a jaw member having anon-stick surface coating may decrease as the amount of surface areacoated increases. However, it may also be suspected that the amount oftissue sealing, which may be related to the quality of the seal, couldbe significantly reduced for a jaw member completely or almostcompletely coated with the electrically non-conductive non-stickmaterial.

However, the effect of such non-stick surface coatings on the quality ofelectrosurgery-based vessel seals has not been well determined.Disclosed below are results of controlled tests of the effect of theamount of electrically non-conducting non-stick coatings on the qualityof electrosurgery-based vessel seals. Such tests measure both theadhesive force of tissue to the jaw members as well as the effectivenessof electrosurgery-based vessel seals produced within the tissues. Suchtests have revealed the unexpected result that jaw members having even ahigh percentage (greater than 70%) of surface coating with anon-conductive non-stick material may produce electrosurgery-basedvessel seals that are functionally equivalent to those formed byuncoated jaw members. Additional tests, not previously seen, furtherreveal the effectiveness of different coating geometries on both theadhesive force and the quality of electrosurgery-based vessel seal. Theresults of such tests demonstrate the additional unexpected result thatthe efficacy of tissue electrosurgery-based vessel seals may furtherdepend on the geometry of the coating on the jaw member and not simplyon the amount of the surface coated with the non-stick material.

For the purpose of this disclosure, the term “patterned coating” isdefined as a material coating on a surface, in which the pattern isdefined by one or more geometric components, and the patterned coatingis specifically fabricated to include the one or more geometriccomponents. In this definition, the term specifically fabricated istaken to mean that the pattern is intentionally designed and that afabrication method of the patterned coating is repeatable or potentiallyrepeatable over any number of surfaces. It may be further understoodthat the patterned coating may include a material coating comprising oneor more portions removed from the material, the patterned coating mayinclude a pattern of portions of the coating material applied to thesurface, or the patterned coating may be fabricated by an overmoldingprocess.

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof. In the drawings,similar symbols and reference characters typically identify similarcomponents throughout the several views, unless context dictatesotherwise.

FIG. 1A shows an electrosurgical instrument 100 in electricalcommunication with a generator 101, according to one aspect of thepresent disclosure. The electrosurgical instrument 100 may beconfigurable with a flexible circuit 102 according to various aspects.The electrosurgical instrument 100 may comprise an elongate member 103,such as a shaft 104, having a proximal portion 105 coupled to a handleassembly 106. A distal portion 107 of the elongate member 103 maycomprise an end effector 108 (see FIG. 1B) coupled to a distal end ofthe shaft 104. In some aspects, the end effector 108 may comprise afirst jaw member 109 a and a second jaw member 109 b, each having anouter portion or surface 110 a, 110 b. At least one of the first jawmember 109 a and the second jaw member 109 b may move relative to theshaft 104. There may be only one jaw movable relative to the shaft 104,and the other jaw may be fixed relative to the shaft 104. At least oneof the first jaw member 109 a and the second jaw member 109 b may berotatably movable relative to the other along a path shown by arrow J totransition the first and second jaw members 109 a, 109 b between openand closed positions. In operation, the first and second jaw members 109a, 109 b may be transitioned from the open position to a closed positionto capture tissue therebetween. Captured tissue may contact one or moreworking portions of the jaw set 111 a, 111 b configured to apply energyto treat target tissue located at or near the end effector 108.

The type of energy may take various forms and includes, withoutlimitation, monopolar and/or bipolar RF energy, microwave energy,reversible and/or irreversible electroporation energy, and/or ultrasonicenergy, or any combination thereof. The handle assembly 106 may comprisea housing 112 defining a grip 113. In various aspects, the handleincludes one or more control interfaces 114 a-c, e.g., a button orswitch 114 a, rotation knob 114 b rotatable along arrow R, and a trigger114 c movable relative to the grip 113 along arrow T, configured toprovide operation instructions to the end effector 108. Multiplebuttons, knobs, or triggers described also may be included as part ofthe housing 112 in order to manipulate one or more of the functioningmembers at the end effector 108. In some aspects, the handle assembly106 may be further configured to electrically couple to a generator 101to supply the electrosurgical instrument 100 with energy.

The generator 101 may be connected to the electrosurgical instrument 100via a suitable transmission medium such as a cable 115. In one example,the generator 101 may be coupled to a controller, such as a control unit116, for example. In various aspects, the control unit 116 may be madeintegrally with the generator 101, or may be provided as a separatecircuit module or device electrically coupled to the generator 101(shown in phantom to illustrate this option). The control unit 116 mayinclude automated or manually operated controls to control the amount ofcurrent delivered by the generator 101 to the electrosurgical instrument100. Although, as presently disclosed, the generator 101 is shownseparate from the electrosurgical instrument 100, in some aspects, thegenerator 101 (and/or the control unit 116) may be made integrally withthe electrosurgical instrument 100 to form a unitary electrosurgicalsystem where a battery located within the electrosurgical instrument 100may be the energy source and a circuit coupled to the battery producesthe suitable electrical energy, ultrasonic energy, or heat energy. Whilethe generator 101 is illustrated as generally coupled to the handleassembly 106, e.g., with a cord, it is to be understood that in someaspects the generator 101 may be positioned within the elongate member103 and/or the handle assembly 106. For example, in one aspect, thegenerator 101 comprises one or more direct current batteries positionedin the handle assembly 106, shaft 104, or a portion thereof.

In one aspect, the generator 101 may comprise an input device located ona front panel of the generator 101. The input device may comprise anysuitable device that generates signals suitable for programming theoperation of the generator 101, such as a keyboard, or input port, forexample. In one example, one or more electrodes in the first jaw 109 aand one or more electrodes in the second jaw member 109 b may be coupledto the generator 101. The cable 115 may comprise multiple electricalconductors for the application of electrical energy to a first electrode(which may be designated as a + electrode) and to a second electrode(which may be designated as a − electrode) of the electrosurgicalinstrument 100. It may be recognized that + and − designations are madesolely for convenience and do not indicate an electrical polarity. Anend of each of the conductors may be placed in electrical communicationwith a terminal of the generator 101. The generator 101 may havemultiple terminals, each configured to contact one or more of theconductors. The control unit 116 may be used to activate the generator101, which may serve as an electrical source. In various aspects, thegenerator 101 may comprise an RF source, an ultrasonic source, a directcurrent source, and/or any other suitable type of electrical energysource, for example, one which may be activated independently orsimultaneously. In various aspects, the cable 115 may comprise at leastone supply conductor 117 and at least one return conductor 118, whereincurrent can be supplied to the electrosurgical instrument 100 via the atleast one supply conductor 117 and wherein the current can flow back tothe generator 101 via the at least one return conductor 118. In variousaspects, the at least one supply conductor 117 and the at least onereturn conductor 118 may comprise insulated wires and/or any othersuitable type of conductor. As described below, the at least one supplyconductor 117 and the at least one return conductor 118 may be containedwithin and/or may comprise the cable 115 extending between, or at leastpartially between, the generator 101 and the end effector 108 of theelectrosurgical instrument 100. The generator 101 can be configured toapply a sufficient voltage differential between the supply conductor 117and the return conductor 118 such that sufficient current can besupplied to the end effector 108 to perform the intended electrosurgicaloperation.

In one example, the generator 101 may be implemented as anelectrosurgery unit (ESU) capable of supplying power sufficient toperform bipolar electrosurgery using RF energy. In one example, the ESUcan be a Force Triad™ Energy Platform sold by Medtronic of Boulder Colo.In some aspects, such as for bipolar electrosurgery applications, anelectrosurgical instrument 100 having an active electrode and a returnelectrode can be utilized, wherein the active electrode and the returnelectrode can be positioned against, adjacent to, and/or in electricalcommunication with the tissue to be treated such that current can flowfrom the active electrode, through the tissue, and to the returnelectrode. Thus, in various aspects, the electrosurgical system maycomprise a supply path and a return path, wherein the captured tissuebeing treated completes, or closes, the circuit. In other aspects, thegenerator 101 may provide sub-therapeutic RF energy levels for purposesof evaluating tissue conditions and providing feedback in theelectrosurgical system. Such feedback may be employed to control thetherapeutic RF energy output of the electrosurgical instrument 100.Sub-therapeutic RF energy levels may be used for bipolar surgicalprocedures if a risk analysis shows the possibility of neuromuscularstimulation has been mitigated to an acceptable level. Under someconditions, frequencies above 5 MHz may not be used in order to minimizeproblems associated with high frequency leakage currents. However,higher frequencies may be used in the case of bipolar techniques.

During operation of electrosurgical instrument 100, the user generallygrasps tissue, supplies energy to the grasped tissue to form a weld or aseal (e.g., by an actuating button and/or pedal), and then drives atissue-cutting member at the distal end of the electrosurgicalinstrument through the grasped tissue. According to various aspects, ajaw-closing member may be provided, and the translation of the axialmovement of the jaw-closing member may be paced, or otherwisecontrolled, to aid in driving the jaw-closing member at a suitable rateof travel. By controlling the rate of travel, the likelihood that thecaptured tissue has been properly and functionally sealed prior totransection with the cutting member may be increased.

FIG. 2 is a perspective view of one example of a first jaw member 109 aof a surgical instrument system 100. The first jaw member 109 a mayinclude at least a first electrode 220. The electrode 220 may comprisean electrically conducting material. In various aspects, the electrode220 of the jaw member 109 a, may be made of metal. The surface of thejaw member 109 a may include thermally conductive components such asstainless steel, copper, silver, aluminum, tungsten, nickel, or anyother thermally conductive materials that may occur to those skilled inthe art. Laminar composites coated with a biocompatible metal coatingmay be applied to the surfaces. The jaw member 109 a may include laminarcomposites of thermally conductive copper and a mechanically strongermaterial, particularly, higher modulus stainless steel. Biocompatibilityof the jaw member 109 a may be maintained through an electro-depositedbiocompatible metal coating, such as chromium, that coats both thestainless steel and copper laminate. In one example, the electrode 220may have a U-shape that surrounds a knife channel 230, in which a knifemay be disposed to reciprocate.

As depicted in FIG. 2 , a non-stick coating 235 may be deposited on orotherwise placed in direct physical communication with the electrodesurface. In some non-limiting examples, the non-stick coating 235 maycomprise an electrically conductive coating. In other non-limitingexamples, the non-stick coating 235 may comprise an electricallynon-conductive coating. While not explicitly depicted in FIG. 2 , thenon-stick coating 235 may be deposited directly on the entire surface ofthe electrode 220 or may be deposited directly on one or more portionsof the surface of the electrode 220. Multiple portions of the non-stickcoating 235 may be contiguous or non-contiguous. In some alternativeaspects, portions of the non-stick coating 235 deposited on the surfaceof the electrode 220 may be removed thereby exposing portions of thesurface of the electrode 220. Alternatively, features comprising one ormore depressions may be fabricated in the surface of the electrode 220and the non-stick coating 235 may be deposited only within thedepressions. It may be understood that the non-stick coating 235 may bedeposited or otherwise placed in direct physical communication with theelectrode surface according to any suitable fabrication method.Non-limiting examples of such fabrication methods may include patternedprinting or the use of an overmolding process.

Although FIG. 2 depicts a first jaw member 109 a, it may be understoodthat a second jaw member 109 b may be similarly coated with a non-stickcoating. The second jaw member 109 b may be coated with the samenon-stick coating as the first jaw member 109 a, or with a differentnon-stick coating. The non-stick coating on the second jaw member 109 bmay be deposited directly on the entire surface of an electrodeassociated with the second jaw member 109 b or may be deposited directlyon one or more portions of the surface of the electrode associated withthe second jaw member 109 b. Multiple portions of the non-stick coatingon the surface of the electrode associated with the second jaw member109 b may be contiguous or non-contiguous. In some alternative aspects,portions of the non-stick coating on the electrode associated with thesecond jaw member 109 b may be removed thereby exposing portions of thesurface of the electrode associated with the second jaw member 109 b.Alternatively, features comprising one or more depressions may befabricated in the surface of the electrode associated with the secondjaw member 109 b and the non-stick coating thereon may be deposited onlywithin the depressions. Further, the disposition of the non-stickcoating on the surface of the first electrode 220 may be the same as ordifferent from the non-stick coating on the surface of the electrodeassociated with the second jaw member 109 b.

FIGS. 3-7 and FIGS. 10-12 depict a variety of aspects of one or more jawmembers comprising electrically non-conducting non-stick coatings.

FIG. 3 depicts a first jaw member 109 a having an electricallyconductive electrode surface that is generally coated with anelectrically non-conducting non-stick coating 335. The non-stick coating335 comprises a patterned coating 345 created by the removal of circularportions 340 of the non-stick coating. In one non-limiting example, suchcircular portions 340 may be removed by machining the non-stick coating335 by a tool such as, in one non-limiting example, by an end-mill. Theremoval of the circular portions 340 may result in the exposure ofportions of the underlying electrode surface. It may be noted that thepatterned non-stick coating 345 comprises a number of linear arrays ofthe circular portions 340, in which the position of the circularportions 340 in the center linear array are offset from the circularportions 340 in the linear arrays on either side.

It should be recognized that the patterned coating 345 depicted in FIG.3 is merely one non-limiting example of a patterned coating. Thus, apatterned coating may comprise a single portion or may have multipleportions removed from the coating 335. The multiple portions may bephysically isolated from each other or may be contiguous. The one ormore portions removed from the non-stick coating 335 may includeportions that are linear, circular, elliptical, oval, rectangular,square, rounded rectangular, or have a geometry defined by any closedtwo-dimensional shape. A patterned coating may include a plurality ofportions 340 having the same shape or may include portions havingdifferent shapes. A patterned coating may include a plurality ofportions having the same size or may include portions having differentsizes. The portions may be disposed in a patterned coating in any numberof ways including, without limitation, regular or irregularly spacedarrays.

The patterned non-stick coating 345 depicted in FIG. 3 may be fabricatedby removing portions of the of the non-stick material, for example byfirst contacting the non-stick material with a surface of the electrodeand then using a fabrication method to remove the portions of thematerial to form the patterned coating. Alternative methods offabricating the patterned non-stick coating 345 may include, forexample, printing the patterned coating directly on the surface of theelectrode. Additional alternative methods for producing the patternedcoating 345 on the electrode may also be employed.

FIG. 4 depicts a first jaw member 409 having an electricallynon-conducting non-stick coating 435 applied to a surface of anelectrode. As distinguished from the non-stick coating 335 depicted inFIG. 3 , the non-stick coating 435 depicted in FIG. 4 is not a patternedcoating. Thus, the non-stick coating 435 depicted in FIG. 4 comprises aplurality of coating defects (observable as discolorations andpin-holes) in the surface of the non-stick coating 435 which may beunderstood as unintended and non-repeatable features of the coating.

FIG. 5 depicts a jaw member 509 having an electrically conductiveelectrode surface 520. The electrode surface 520 includes a plurality ofrecessed features 542. In FIG. 5 , the recessed features 542 comprise aplurality of circular recessed features 542. The non-stick coating 540may be applied to or in the plurality of recessed features 542. Thepatterned non-stick coating 545 may comprise the plurality of non-stickcoatings 540 applied to or in the plurality of recessed features 542. Itmay be noted that the patterned non-stick coating 545 comprises a numberof linear arrays of the circular recessed features 542 having thenon-stick coating 540 applied to or in the recessed features 542, inwhich the linear arrays are oblique to a longitudinal axis of the jawmember 509. The non-stick coating 540 may completely fill the recessedfeatures 542, thereby forming a surface co-planar with the electricallyconductive electrode surface 520. In an alternative aspect, thenon-stick coating 540 may incompletely fill the recessed features 542,thereby forming a surface recessed from the electrically conductiveelectrode surface 520. In yet an additional aspect, the non-stickcoating 540 may overfill the recessed features 542, thereby forming asurface protruding above the electrically conductive electrode surface520.

It should be recognized that the patterned coating 545 depicted in FIG.5 is merely one non-limiting example of a patterned coating. Thus, apatterned coating may comprise a non-stick coating applied to or in asingle recessed feature or multiple recessed features. The recessedfeatures may be physically isolated from each other or may becontiguous. The one or more recessed features may extend partiallythrough a thickness of the electrode. Alternatively, the one or morerecessed features may extend completely through the thickness of theelectrode, thereby allowing the recessed feature to receive thenon-stick coating either from a top side or a bottom side of theelectrode, for example as part of an overmolding process. The one ormore recessed features may include recessed features that are linear,circular, elliptical, oval, rectangular, square, rounded rectangular, orhave a geometry defined by any closed two-dimensional shape. A patternedcoating may include the non-stick coating disposed within a plurality ofrecessed features having the same shape or may include recessed featureshaving different shapes. A patterned coating may include the non-stickcoating disposed within a plurality of recessed features having the samesize or may include recessed features having different sizes. Thepattern coating may include the non-stick coating disposed withinrecessed features that may be disposed in a surface of an electrode inany number of ways including, without limitation, regular or irregularlyspaced arrays.

The patterned non-stick coating 545 depicted in FIG. 5 may be fabricatedby removing portions from the surface of the electrode to form therecessed features, for example by the use of an end-mill, and then usinga fabrication method to deposit the non-stick material in the recessedfeatures to form the patterned coating. Alternative methods offabricating the patterned non-stick coating 545 may include, forexample, molding the electrode to include the recessed features beforedepositing the non-stick materials therewithin. Additional alternativemethods for producing the patterned coating 545 on the electrode mayalso be employed.

FIG. 6 depicts a jaw member 609 having an electrically conductiveelectrode surface 620. The electrode surface 620 includes a plurality ofrecessed features 642. In FIG. 6 , the recessed features 642 comprise aplurality of elongated recessed features 642. The non-stick coating 640may be applied to or in the plurality of recessed features 642. Thepatterned non-stick coating 645 may comprise the plurality of non-stickcoating 640 applied to or in the plurality of recessed features 642. Itmay be noted that the patterned non-stick coating 645 comprises thenon-stick coating 640 applied to or in the plurality of elongatedrecessed features 642 that are arrayed along or parallel to thelongitudinal axis of the jaw member 609. The non-stick coating 640 maycompletely fill the recessed features 642, thereby forming a surfaceco-planar with the electrically conductive electrode surface 620. In analternative aspect, the non-stick coating 640 may incompletely fill therecessed features 642, thereby forming a surface recessed from theelectrically conductive electrode surface 620. In yet an additionalaspect, the non-stick coating 640 may overfill the recessed features642, thereby forming a surface protruding above the electricallyconductive electrode surface 620.

It should be recognized that the patterned coating 645 depicted in FIG.6 is merely one non-limiting example of a patterned coating. Thus, apatterned coating may comprise a single elongated recessed feature ormay have multiple elongated recessed features. The elongated recessedfeatures may be physically isolated from each other or may becontiguous. The one or more recessed features may extend partiallythrough a thickness of the electrode. Alternatively, the one or morerecessed features may extend completely through the thickness of theelectrode, thereby allowing the recessed feature to receive thenon-stick coating either from a top side or a bottom side of theelectrode, for example as part of an overmolding process. More complexpatterned coatings may be derived from combinations of elongatedrecessed features to form, a non-limiting examples, a herring-bonepattern or a T-shaped pattern, A patterned coating may include thenon-stick coating disposed within a plurality of elongated recessedfeatures having the same shape or may include elongated recessedfeatures having different shapes. For example, the elongated featuresmay have the same length or may have different lengths. Additionally,the elongated features may have the same width or may have differentwidths. The pattern coating may include the non-stick coating disposedwithin elongated recessed features that may be disposed in a surface ofan electrode in any number of ways including, without limitation,regular or irregularly spaced arrays.

The patterned non-stick coating 645 depicted in FIG. 6 may be fabricatedby removing portions from the surface of the electrode to form theelongated recessed features, for example by the use of an end-mill, andthen using a fabrication method to deposit the non-stick material in theelongated recessed features to form the patterned coating. Alternativemethods of fabricating the patterned non-stick coating 645 may include,for example, molding the electrode to include the elongated recessedfeatures before depositing the non-stick materials therewithin.Additional alternative methods for producing the patterned coating 645on the electrode may also be employed.

FIG. 7 depicts a close-up view of a jaw member having an electricallyconductive electrode surface 720. The electrode surface 720 includes aplurality of recessed features 742. In FIG. 7 , the recessed features742 comprise a plurality of elongated recessed features 742. Thenon-stick coating 740 may be applied to or in the plurality of recessedfeatures 742. The patterned non-stick coating 745 may comprise theplurality of non-stick coating 740 applied to or in the plurality ofrecessed features 742. It may be noted that the patterned non-stickcoating 745 comprises the non-stick coating 740 applied to or in theplurality of elongated recessed features 742 that are arrayed along orparallel to a transverse axis 780 of the jaw member. The non-stickcoating 740 may completely fill the recessed features 742, therebyforming a surface co-planar with the electrically conductive electrodesurface 720. In an alternative aspect, the non-stick coating 740 mayincompletely fill the recessed features 742, thereby forming a surfacerecessed from the electrically conductive electrode surface 720. In yetan additional aspect, the non-stick coating 740 may overfill therecessed features 742, thereby forming a surface protruding above theelectrically conductive electrode surface 720.

It should be recognized that the patterned coating 745 depicted in FIG.7 is merely one non-limiting example of a patterned coating. Thus, apatterned coating may comprise a single elongated recessed feature ormay have multiple elongated recessed features. The elongated recessedfeatures may be physically isolated from each other or may becontiguous. The one or more recessed features may extend partiallythrough a thickness of the electrode. Alternatively, the one or morerecessed features may extend completely through the thickness of theelectrode, thereby allowing the recessed feature to receive thenon-stick coating either from a top side or a bottom side of theelectrode, for example as part of an overmolding process. More complexpatterned coatings may be derived from combinations of elongatedrecessed features to form, a non-limiting examples, a herring-bonepattern or a T-shaped pattern, A patterned coating may include thenon-stick coating disposed within a plurality of elongated recessedfeatures having the same shape or may include elongated recessedfeatures having different shapes. For example, the elongated featuresmay have the same length or may have different lengths. Additionally,the elongated features may have the same width or may have differentwidths. The pattern coating may include the non-stick coating disposedwithin elongated recessed features that may be disposed in a surface ofan electrode in any number of ways including, without limitation,regular or irregularly spaced arrays.

The patterned non-stick coating 745 depicted in FIG. 7 may be fabricatedby removing portions from the surface of the electrode to form theelongated recessed features, for example by the use of an end-mill, andthen using a fabrication method to deposit the non-stick material in theelongated recessed features to form the patterned coating. Alternativemethods of fabricating the patterned non-stick coating 745 may include,for example, molding the electrode to include the elongated recessedfeatures before depositing the non-stick materials therewithin.Additional alternative methods for producing the patterned coating 745on the electrode may also be employed.

FIG. 8 depicts a box plot of measurements of average total stickingforce (lbf) for tissues sealed using an electrosurgical device having ajaw member that includes an electrode comprising a variety of patternednon-stick coating. The total adhesion force is the integral of thetissue sticking force over the surface area where sticking occurs. Byreducing the area of sticking, the total sticking force can be reduced.In FIG. 8 , the patterned non-stick coating is similar to that depictedin FIG. 7 and the non-stick material may be a fluoropolymer. The testtissue materials used in FIG. 8 are samples of carotid artery material.FIG. 8 compares the total sticking force of the tissues sealed by jawmembers in which the electrode has a surface comprising a defined amountof surface area covered by the non-stick material. A control result,using an uncoated electrode, is included for comparison. The amount ofsurface area of the electrode covered by the non-stick material ispresented as a percent of the total surface area of the electrode thatis covered by the non-stick material. Thus, the percent total surfacearea of the electrode covered by the non-stick material may becalculated as

${\frac{A_{m}}{A_{t}} \times 100},$

where A_(t) is the total surface area of the electrode, and A_(m) is theamount of the total surface area of the electrode covered by thenon-stick material.

The box plot in FIG. 8 shows the average sticking force in lbf forcarotid tissues sealed by an electrode having a 45%, 68%, and 76%surface coating of the fluoropolymer. As indicated in FIG. 8 , theaverage total sticking force of the material to the electrodes havingthe three values of percent total surface area covered by the non-stickmaterial are about 0.232 lbf, 0.199 lbf, and 0.125 lbf, respectively.These values may be compared to the value of 0.342 lbf for the control,uncoated, electrode. The boxplot suggests that the average stickingforce for tissue to the electrodes decreases as the percent totalsurface area covered by the fluoropolymer increases. It is especiallynoted that the average sticking force for tissue to an electrode having76% of its surface coated with the fluoropolymer appears to besignificantly less than the control, uncoated electrode.

FIG. 9 depicts a box plot of the average burst pressure (in mmHg) ofcarotid artery samples sealed using an electrode having a non-stickmaterial coating pattern as illustrated in FIG. 7 . FIG. 9 compares theaverage burst pressure for carotid artery samples sealed using anelectrode have a percent total surface area covered by the non-stickcoating of about 76% with the average burst pressure of carotid arterysamples sealed using an uncoated electrode. The data in FIG. 9 wereanalyzed using the Tukey method, and no statistically significantdifference was found between the two sets of samples.

The experimental result depicted in FIG. 9 illustrates the unexpectedresult that the quality of the electrosurgery-based vessel seal on atissue is effectively unaffected even when the contact area of theconductive portion of the electrode is reduced to less than a quarter ofthe total surface area of the electrode. Without being bound by theory,the effect of reduced contact area on the electrical transmission of theRF energy to the tissue may be minimal because an electric current canflow laterally through the holes in the coating. FIG. 16 illustratespossible current flow pathways 1680 through a tissue 1690 compressedbetween a first electrode 1609 a and a second electrode 1609 b. Each ofthe first electrode 1609 a and second electrode 1609 b includes apatterned coating of a non-stick material, 1635 a,b, respectively.Portions 1640 a,b have been removed from the patterned coatings of thenon-stick material 1635 a,b, respectively, thereby exposing theelectrically conductive surface of the respective electrodes 1609 a,bunderneath. It may be recognized that the portions 1640 a,b removed fromthe patterned coatings of the non-stick material 1635 a,b may providesmall conductive pathways for an electrical current to flow 1680. Thesmall conductive pathways may enable adequate electric current to flow1680 into the tissue 1690 to raise the temperature via joule heating. Asa result, the quality of the seal of a tissue sealed by an electrodehaving a 76% non-conductive surface coating may be about the same as thequality of the seal of a tissue sealed by an uncoated electrode.

FIGS. 10A-D depict a variety of aspects of patterned coatings ofnon-stick material on an electrode component of an electrosurgicalinstrument. Thus, FIG. 10A depicts a first jaw member 1009 a having apatterned non-stick coating 1045 a on an electrode surface comprising anon-stick coating 1035 a from which one or more circular portions 1040 ahave been removed, thereby uncovering the electrode surface therebelow.The patterned non-stick coating 1045 a depicted in FIG. 10A may befabricated by removing portions of the of the non-stick material, forexample by first contacting the non-stick material with a surface of theelectrode and then using a fabrication method to remove the portions ofthe material to form the patterned coating 1045 a. Alternative methodsof fabricating the patterned non-stick coating 1045 a may include, forexample, printing the patterned coating directly on the surface of theelectrode. Additional alternative methods for producing the patternednon-stick coating 1045 a on the electrode may also be employed.

In some aspects, the percent total surface area of the electrode coveredby the patterned non-stick coating 1045 a as depicted in FIG. 10A may beadjusted by altering the number of the one or more circular portions1040 a removed from the non-stick coating 1035 a. In some alternativeaspects, the percent total surface area of the electrode covered by thepatterned non-stick coating 1045 a as depicted in FIG. 10A may beadjusted by altering the size of the one or more circular portions 1040a removed from the non-stick coating 1035 a. In some additional aspects,the percent total surface area of the electrode covered by the patternednon-stick coating 1045 a as depicted in FIG. 10A may be adjusted byaltering the shape of the one or more circular portions 1040 a removedfrom the non-stick coating 1035 a. It may be understood that the percenttotal surface area of the electrode covered by the patterned non-stickcoating 1045 a as depicted in FIG. 10A may be adjusted by altering anyone or more of the number, size, or shape of the one or more circularportions 1040 a removed from the non-stick coating 1035 a.

FIG. 10B depicts a first jaw member 1009 a having a patterned non-stickcoating 1045 b on an electrode surface comprising a non-stick coating1035 b from which one or more square or rectangular portions 1040 b havebeen removed, thereby uncovering the electrode surface therebelow. Thepatterned non-stick coating 1045 b depicted in FIG. 10A may befabricated by removing portions of the of the non-stick material, forexample by first contacting the non-stick material with a surface of theelectrode and then using a fabrication method to remove the portions ofthe material to form the patterned coating 1045 b. Alternative methodsof fabricating the patterned non-stick coating 1045 b may include, forexample, printing the patterned coating directly on the surface of theelectrode. Additional alternative methods for producing the patternednon-stick coating 1045 b on the electrode may also be employed.

In some aspects, the percent total surface area of the electrode coveredby the patterned non-stick coating 1045 b as depicted in FIG. 10B may beadjusted by altering the number of the one or more square or rectangularportions 1040 b removed from the non-stick coating 1035 b. In somealternative aspects, the percent total surface area of the electrodecovered by the patterned non-stick coating 1045 b as depicted in FIG.10B may be adjusted by altering the size of the one or more square orrectangular portions 1040 b removed from the non-stick coating 1035 b.In some additional aspects, the percent total surface area of theelectrode covered by the patterned non-stick coating 1045 b as depictedin FIG. 10B may be adjusted by altering the shape of the one or moresquare or rectangular portions 1040 b removed from the non-stick coating1035 b. It may be understood that the percent total surface area of theelectrode covered by the patterned non-stick coating 1045 b as depictedin FIG. 10A may be adjusted by altering any one or more of the number,size, or shape of the one or more square or rectangular portions 1040 bremoved from the non-stick coating 1035 b.

FIGS. 10C and 10D depict a surface view of a first jaw member 1009 a anda top view of a second jaw member 1009 b, respectively, each having apatterned non-stick coating 1045 c and 1045 d, respectively, on a firstand second electrode surface. Each patterned non-stick coating 1045 cand 1045 d may comprise a non-stick coating 1035 c and 1035 d,respectively, from which one or more elongated portions 1040 c and 1040d, respectively, have been removed, thereby uncovering the respectiveelectrode surfaces therebelow. The patterned non-stick coatings 1045 cand 1045 d depicted in FIGS. 10C and 10D may be fabricated by removingportions of the of the non-stick material, for example by firstcontacting the non-stick material with a surface of the electrode andthen using a fabrication method to remove the portions of the materialto form the patterned coatings 1045 c,d. Alternative methods offabricating the patterned non-stick coatings 1045 c,d may include, forexample, printing the patterned coating directly on the surface of theelectrode. Additional alternative methods for producing the patternednon-stick coatings 1045 c,d on the electrodes may also be employed.

FIG. 10C depicts a view of the surface of jaw member 1009 a, while FIG.10D depicts a top view of the second jaw member 1009 b, in which thepatterned coating 1045 d is seen as a projection. Depending on the sizeand shape of the elongated portions 1040 c and 1040 d, placing the firstjaw member 1009 a in FIG. 10C proximate to the second jaw member 1009 bin FIG. 10D may result in no overlap, a partial overlap, ora completeoverlap of the elongated portion 1040 c with elongated portion 1040 d.In an example of the patterned coating 1045 c and patterned coating 1045d in which there is no overlap between elongated portion 1040 c withelongated portion 1040 d, it is possible that a transmission of an RFelectric current between the first electrode and the second electrodemay result in the current being transmitted in a transverse mannerthrough a tissue compressed therebetween. Alternatively, if there is atleast some overlap between elongated portion 1040 c with elongatedportion 1040 d, it is possible that a transmission of an RF electriccurrent between the first electrode and the second electrode may resultin the current being transmitted in a vertical manner through a tissuecompressed therebetween

In some aspects, the percent total surface area of the electrode coveredby the patterned non-stick coating 1045 c,d as depicted in FIGS. 10C and10D, respectively, may be adjusted by altering the number of the one ormore elongated portions 1040 c,d removed from the respective non-stickcoatings 1035 c,d. In some alternative aspects, the percent totalsurface area of the electrode covered by the patterned non-stickcoatings 1045 c,d as depicted in FIGS. 10C and 10D, respectively, may beadjusted by altering the size (length and/or width) of the one or moreelongated portions 1040 c,d removed from the respective non-stickcoatings 1035 c,d. In some additional aspects, the percent total surfacearea of the electrodes covered by the patterned non-stick coatings 1045c,d as depicted in FIGS. 10C and 10D, respectively, may be adjusted byaltering the shape of the one or more elongated portions 1040 c,dremoved from the respective non-stick coatings 1035 c,d. It may beunderstood that the percent total surface area of the electrodes coveredby the patterned non-stick coating 1045 c,d as depicted in FIGS. 10C and10D, respectively, may be adjusted by altering any one or more of thenumber, size (length and/or width), or shape of the one or moreelongated portions 1040 c,d removed from the respective non-stickcoatings 1035 c,d.

FIG. 11 illustrates a first group of patterned non-stick coatings forelectrodes used to test an amount of sticking force of a tissue to thepatterned coated electrode as well as burst pressure tests for sealsmade on the tissue (for example a carotid artery). The patternedcoatings depicted in FIG. 11 were similar to those depicted in FIG. 10A.The patterned coatings were made from a non-stick coating 1135 of anelectrically non-conducting material (a form of polytetrafluoroethylene)from which circular portions 1140 had been removed. The test electrodescomprised four (4) correction zones. In correction zone 1, having afirst pattern 1160, no material had been removed from the non-stickcoating 1135. In zone 2, having a second pattern 1162, zone 3, having athird pattern 1164, and zone 4, having a fourth pattern 1166, varyingamounts of material had been removed from the non-stick coating 1135.The second, third, and fourth patterns, 1162, 1164, 1166, respectively,were fabricated by the removal of a variety of numbers of circularportions 1140. It should be noted that the circular portions 1140removed from the non-stick coating 1135 in zones 2-4 all had the samesize and shape. Thus, the percent total surface areas of the electrodescovered by the patterned non-stick coatings 1162, 1164, 1166, dependedonly on the relative number of circular portions 1140 removed from thenon-stick coating 1135 in the respective corrective zones.

Although not illustrated, a second group of patterned non-stick coatingsfor electrodes were used to test an amount of sticking force of a tissueto the patterned coated electrode as well as burst pressure tests forseals made on the tissue (for example a carotid artery). The secondgroup of patterned non-stick coatings was based on the patternedcoatings depicted in FIG. 10B. Patterned coatings were made from anon-stick coating of an electrically non-conducting material (a form ofpolytetrafluoroethylene) from which square portions had been removed.The test electrodes having the patterned coatings depicted in FIG. 10Bcomprised four (4) correction zones. In correction zone 1, having afirst pattern, no material had been removed from the non-stick coating.In zone 2, zone 3, and zone 4, varying amounts of material had beenremoved from the non-stick coating. The second, third, and fourthpatterns, respectively, were fabricated by the removal of a variety ofnumbers of square portions. It should be noted that the square portionsremoved from the non-stick coating in zones 2-4 all had the same sizeand shape. Thus, the percent total surface areas of the electrodescovered by the patterned non-stick coatings depended only on therelative number of square portions removed from the non-stick coating inthe respective corrective zones.

FIG. 12 illustrates a third group of patterned non-stick coatings forelectrodes used to test an amount of sticking force of a tissue to thepatterned coated electrode as well as burst pressure tests for sealsmade on the tissue (for example a carotid artery). The patternedcoatings depicted in FIG. 12 were similar to those depicted in FIGS. 10Cand 10D. The test electrodes comprised top test electrodes 1209 a, 1219a and bottom test electrodes 1209 b, 1219 b. The test electrodes may berelated to electrodes that form components of a first jaw member and asecond jaw member, respectively, of an electrosurgical device. Thepatterned coatings on top electrodes 1209 a, 1219 a were made from anon-stick coating 1235 a of an electrically non-conducting material (aform of polytetrafluoroethylene). The patterned coatings on bottomelectrodes 1209 b, 1219 b were made from a non-stick coating 1235 b ofan electrically non-conducting material (a form ofpolytetrafluoroethylene). Although the test electrodes 1290 a,b and 1219a,b were coated with the same electrically non-conducting material forthe purposes of the tests disclosed herein, it may be recognized thatsuch compositions are not limiting. Thus, patterned non-stick coating ofa first electrode and a second electrode may comprise the same materialor may comprise different materials. As part of the test protocol, thetop test electrodes 1209 a, 1219 a and bottom test electrodes 1209 b,1219 b were fabricated to have two different thicknesses of thenon-stick coating 1235 a,b. One set of test electrodes were fabricatedwith a non-stick coating 1235 a,b having a thickness of about 0.020inches. A second set of test electrodes were fabricated with a non-stickcoating 1235 a,b having a thickness of about 0.032 inches.

The patterned non-stick coatings on the top electrodes 1209 a, 1219 aand bottom electrodes 1209 b, 1219 b were formed from the respectivenon-stick coatings 1235 a,b from which elongated portions 1240 a-c and1242 a-c had been removed. The test electrodes comprised four (4)correction zones. In correction zone 1, having a first pattern 1260, nomaterial had been removed from the non-stick coatings 1235 a,b. In zone2, having a second pattern 1262, zone 3, having a third pattern 1264,and zone 4, having a fourth pattern 1266, varying amounts of materialhad been removed from the non-stick coatings 1235 a,b of each of the topelectrodes 1209 a, 1219 a and bottom electrodes 1209 b, 1219 b therebyexposing the surface of the respective electrodes therebelow.

The elongated portions 1240 a, 1242 a removed from the second pattern1262, 1240 b, 1242 b removed from the third pattern 1264, and 1240 c,1242 c removed from the fourth pattern 1266 all had about the samelength but differed in their respective widths. Thus, the percent totalsurface areas of the electrodes covered by the patterned non-stickcoatings 1262, 1264, 1266, depended only on the relative widths of therespective elongated portions removed from the non-stick coating 1235a,b in the respective corrective zones. It may be recognized from FIG.12 that when the top electrodes 1209 a, 1219 a are brought in a proximalposition to the respective bottom electrodes 1209 b, 1219 b, portions ofthe respective top elongated portions may form some amount of overlapwith the respective bottom elongated portions depending on the relativewidths of the top elongated portions and the bottom elongated portions.For example, in zone 2, the respective widths of the elongated portions1240 a and 1242 a are sufficiently narrow so that no overlap of theelongated portions occurs. Accordingly, for patterned non-stick coating1262, an electric current passing from the top electrode 1219 a to thebottom electrode 1219 b would pass only in a transverse manner throughany tissue compressed therebetween. In zone 3, the respective widths ofthe elongated portions 1240 b and 1242 b do not permit overlap of theelongated portions, but the edges of the respective elongated portionsmay be nearly aligned. Accordingly, for patterned non-stick coating1264, an electric current passing from the top electrode 1219 a to thebottom electrode 1219 b may pass in an oblique manner between the edgesof the respective elongated portions through any tissue compressedtherebetween. In zone 4, the respective widths of the elongated portions1240 c and 1242 c are sufficiently wide so that some amount of overlapof the elongated portions may occur. Accordingly, for patternednon-stick coating 1266, an electric current passing from the topelectrode 1209 a to the bottom electrode 1209 b would pass only in avertical manner through any tissue compressed therebetween.

Tests were conducted using electrodes having patterned non-stickcoatings as disclosed above and as depicted in FIGS. 10A-D, 11, and 12on samples of carotid arteries. The tests were designed to determineeffects on both tissue sticking force and the quality of theelectrosurgery-based vessel seal for tissues sealed using electrodeshaving different geometries and percent total surface area covered bythe non-stick material. Table 2 discloses the amount of percent totalsurface area covered by the non-stick material for the correction zonesdisclosed above for each of the non-stick coating patterns. It may beunderstood that higher values for the correction zone numbercorresponded to electrodes having greater portions of the non-stickcoating removed from the surface (either a greater number of circular orsquare portions removed from the coating, or by a larger width of theelongated portion).

TABLE 2 Percent Total Surface Area Covered by Non-stick MaterialCorrection Circular Square Elongated Zone Hole Pattern Hole PatternPattern Number (see FIG. 11) (Equivalent to FIG. 11) (See FIG. 12) 1 100100 100 2 80.6 76 79.9 3 66.5 60.6 66.6 4 50 51.5 56.6The graphs presented in FIGS. 13-15 reference this table by correctionzone number.

FIG. 13 presents a box plot of the amount of sticking force (lbf) ofsample carotid arteries to each of the sample electrodes depicted inFIGS. 10-12 and as disclosed above. The electrodes are referenced by thepatterned non-stick coatings (correction zones 1-4) and types ofpatterned geometries. The “Correction Zone” values correspond to percenttotal surface area covered by the non-stick material as disclosed inTable 2, above. The “control” electrode is one having an electricallyconducting silicon coating on the entire electrode surface. The “holes”pattern references the pattern depicted in FIGS. 10A and 11 . The“waffle” pattern references the pattern depicted in FIG. 10B, disposedin correction zone geometries equivalent to those of the hole patternsdepicted in FIG. 11 . The “offset” pattern references the patterndepicts in FIGS. 10C and D and FIG. 12 . Two versions of the “offset”pattern are presented, one in which the thickness of the non-stickmaterial is about 0.02 inches thick, and the other in which thethickness of the non-stick material is about 0.032 inches thick. It maybe noted that the vessels that were tested on two of the zones (Zones 2& 4) for the 0.032″ thick offset electrode were two-days old, as opposedto the one-day old vessels that were tested on the other zones. It maybe observed that the sticking force for tissue sealed using the controlelectrode is widely distributed, while the sticking force for samplessealed using the patterned non-stick coatings were generally morenarrowly distributed. Such results suggest that the patterned coatingsresulted in much more repeatable sticking force of the tissues to thesurface of the electrodes.

FIG. 14 presents a box plot of the burst pressure (in mmHg) of samplecarotid arteries after a electrosurgery-based vessel seal had beenapplied by each of the sample electrodes depicted in FIGS. 10-12 and asdisclosed above. The electrodes are referenced by the patternednon-stick coatings (correction zones 1-4) and types of patternedgeometries. The “Correction Zone” values correspond to percent totalsurface area covered by the non-stick material as disclosed in Table 2,above. The “control” electrode is one having an electrically conductingsilicon coating on the entire electrode surface. The “holes” patternreferences the pattern depicted in FIGS. 10A and 11 . The “waffle”pattern references the pattern depicted in FIG. 10B, disposed incorrection zone geometries equivalent to those of the hole patternsdepicted in FIG. 11 . The “offset” pattern references the patterndepicts in FIGS. 10C and D and FIG. 12 . Two versions of the “offset”pattern are presented, one in which the thickness of the non-stickmaterial is about 0.02 inches thick, and the other in which thethickness of the non-stick material is about 0.032 inches thick. It maybe noted that the vessels that were tested on two of the zones (Zones 2& 4) for the 0.032″ thick offset electrode were two-days old, as opposedto the one-day old vessels that were tested on the other zones.

It may be recognized that an optimal patterned non-stick materialcoating comprising an electrically non-conducting material may be onethat minimizes the sticking force of the tissue to the electrode andmaximizes the burst pressure of the seal created by the electrode. FIG.15 depicts a main effects plot for the sticking force of the carotidartery sample to the electrodes. The main effects plot aggregates theresults depicted in FIG. 13 by electrode type in the left-hand portionof the plot, and aggregates the results depicted in FIG. 13 bycorrection zone (that is, by percent total surface area covered by thenon-stick material) in the right-hand portion of the plot. It may beobserved that tissue samples sealed using electrodes having any of thenon-stick material coating patterns had a lower average sticking forcevalues to the electrodes than the control. In addition, little variationin average sticking force of the tissue to the electrodes was observedregardless of the pattern used.

FIGS. 3-7 and 19-12 and their descriptions as disclosed above present aplurality of aspects of a jaw members comprising a plurality ofnon-stick coating patterns. Although a plurality of aspects of suchcoating patterns has been disclosed herein, such aspects are not to beconstrued as limiting. Thus, the coating patterns may include anyappropriate coating patterns that may be configured on a surface of oneor more jaw members or electrodes. The coating patterns may generallyinclude coating patterns applied to a planar surface of an electrode, toone or more raised or elevated features that extend vertically above asurface of an electrode, or to one or more depressed features thatextend vertically below a surface of an electrode. It may be understoodthat the term “non-stick material disposed on an electrode” encompassesthe application of the material on a planar surface of an electrode, toone or more raised or elevated features that extend vertically above asurface of an electrode, or to one or more depressed features thatextend vertically below a surface of an electrode. No limitations,expressed or implied, are herein imposed on methods of fabricating thecoating patterns.

The coating patterns may include a single feature or multiple features.The single feature or multiple features may have a limited extent, suchas a small circular portion of the non-stick material disposed on anelectrode (for example, FIG. 5 ) or a small circular portion removedfrom a non-stick material coating the electrode (for example, FIG. 3 ).The single feature or multiple features may have a more extended extentsuch as an elongated portion of the non-stick material disposed on anelectrode (for example, FIGS. 6 and 7 ) or an elongated portion removedfrom a non-stick material coating the electrode (for example, FIGS.10C,D). The single feature or multiple features—either of limited extentor of extended extent—are not limited in their respective shapes, sizes,or dimensions on an electrode surface. The single feature or multiplefeatures—either of limited extent or of extended extent—are not limitedin their respective dispositions about the surface of the electrode.Thus, as an example, elongated portion of the non-stick material mayextend along an axis essentially parallel to a longitudinal axis of theelectrode. Alternatively, an elongated portion of the non-stick materialmay extend along an axis essentially perpendicular to a longitudinalaxis of the electrode. In yet another alternative example, an elongatedportion of the non-stick material may extend along an axis neitheressentially parallel to nor essentially perpendicular to a longitudinalaxis of the first electrode.

The coating patterns may include multiple features that may include anycombination or combinations of portions of the non-stick materialdisposed on an electrode surface or portions removed from a coating of anon-stick material disposed on the electrode surface. Multiple featuresmay be combined. Further, multiple features may be symmetricallydisposed about the surface of the electrode or they may beasymmetrically disposed about the surface of the electrode. Multiplefeatures—either of limited extent or of extended extent—are not limitedin their dispositions about the surface of the electrode with respect toeach other.

An electrosurgical device such as that depicted in FIGS. 1A,B maycomprise multiple jaws each having an electrode. A patterned non-stickcoating may be applied to any one or more of the multiple electrodes.The patterned non-stick coating applied to any one of the multipleelectrodes may comprise the same non-stick material as a patternednon-stick coating applied to any other of the multiple electrodes.Alternatively, the patterned non-stick coating applied to any one of themultiple electrodes may comprise a different non-stick material thanthat comprising a patterned non-stick coating applied to any other ofthe multiple electrodes. A non-stick coating pattern applied to any oneof the multiple electrodes may comprise the same non-stick coatingpattern applied to any other of the multiple electrodes. Alternatively,the non-stick coating patterned applied to any one of the multipleelectrodes may comprise a different non-stick coating pattern than anon-stick coating pattern applied to any other of the multipleelectrodes.

While various aspects herein have been illustrated by description ofseveral aspects and while the illustrative embodiments have beendescribed in considerable detail, it is not the intention of theapplicant to restrict or in any way limit the scope of the appendedclaims to such detail. Additional advantages and modifications mayreadily appear to those skilled in the art. For example, it is generallyaccepted that endoscopic procedures are more common than laparoscopicprocedures. Accordingly, the present invention has been discussed interms of endoscopic procedures and apparatus. However, use herein ofterms such as “endoscopic”, should not be construed to limit the presentinvention to an instrument for use only in conjunction with anendoscopic tube (e.g., trocar). On the contrary, it is believed that thepresent invention may find use in any procedure where access is limitedto a small incision, including but not limited to laparoscopicprocedures, as well as open procedures.

Further, while several forms have been illustrated and described, it isnot the intention of the applicant to restrict or limit the scope of theappended claims to such detail. Numerous modifications, variations,changes, substitutions, combinations, and equivalents to those forms maybe implemented and will occur to those skilled in the art withoutdeparting from the scope of the present disclosure. Moreover, thestructure of each element associated with the described forms can bealternatively described as a means for providing the function performedby the element. Also, where materials are disclosed for certaincomponents, other materials may be used. It is therefore to beunderstood that the foregoing description and the appended claims areintended to cover all such modifications, combinations, and variationsas falling within the scope of the disclosed forms. The appended claimsare intended to cover all such modifications, variations, changes,substitutions, modifications, and equivalents.

For conciseness and clarity of disclosure, selected aspects of theforegoing disclosure have been shown in block diagram form rather thanin detail. Some portions of the detailed descriptions provided hereinmay be presented in terms of instructions that operate on data that isstored in one or more computer memories or one or more data storagedevices (e.g. floppy disk, hard disk drive, Compact Disc (CD), DigitalVideo Disk (DVD), or digital tape). Such descriptions andrepresentations are used by those skilled in the art to describe andconvey the substance of their work to others skilled in the art. Ingeneral, an algorithm refers to a self-consistent sequence of stepsleading to a desired result, where a “step” refers to a manipulation ofphysical quantities and/or logic states which may, though need notnecessarily, take the form of electrical or magnetic signals capable ofbeing stored, transferred, combined, compared, and otherwisemanipulated. It is common usage to refer to these signals as bits,values, elements, symbols, characters, terms, numbers, or the like.These and similar terms may be associated with the appropriate physicalquantities and are merely convenient labels applied to these quantitiesand/or states.

Unless specifically stated otherwise as apparent from the foregoingdisclosure, it is appreciated that, throughout the foregoing disclosure,discussions using terms such as “processing” or “computing” or“calculating” or “determining” or “displaying” or the like, refer to theaction and processes of a computer system, or similar electroniccomputing device, that manipulates and transforms data represented asphysical (electronic) quantities within the computer system's registersand memories into other data similarly represented as physicalquantities within the computer system memories or registers or othersuch information storage, transmission or display devices.

In a general sense, those skilled in the art will recognize that thevarious aspects described herein which can be implemented, individuallyand/or collectively, by a wide range of hardware, software, firmware, orany combination thereof can be viewed as being composed of various typesof “electrical circuitry.” Consequently, as used herein “electricalcircuitry” includes, but is not limited to, electrical circuitry havingat least one discrete electrical circuit, electrical circuitry having atleast one integrated circuit, electrical circuitry having at least oneapplication specific integrated circuit, electrical circuitry forming ageneral purpose computing device configured by a computer program (e.g.,a general purpose computer configured by a computer program which atleast partially carries out processes and/or devices described herein,or a microprocessor configured by a computer program which at leastpartially carries out processes and/or devices described herein),electrical circuitry forming a memory device (e.g., forms of randomaccess memory), and/or electrical circuitry forming a communicationsdevice (e.g., a modem, communications switch, or optical-electricalequipment). Those having skill in the art will recognize that thesubject matter described herein may be implemented in an analog ordigital fashion or some combination thereof.

The foregoing detailed description has set forth various forms of thedevices and/or processes via the use of block diagrams, flowcharts,and/or examples. Insofar as such block diagrams, flowcharts, and/orexamples contain one or more functions and/or operations, it will beunderstood by those within the art that each function and/or operationwithin such block diagrams, flowcharts, and/or examples can beimplemented, individually and/or collectively, by a wide range ofhardware, software, firmware, or virtually any combination thereof. Inone form, several portions of the subject matter described herein may beimplemented via an application specific integrated circuits (ASIC), afield programmable gate array (FPGA), a digital signal processor (DSP),or other integrated formats. However, those skilled in the art willrecognize that some aspects of the forms disclosed herein, in whole orin part, can be equivalently implemented in integrated circuits, as oneor more computer programs running on one or more computers (e.g., as oneor more programs running on one or more computer systems), as one ormore programs running on one or more processors (e.g., as one or moreprograms running on one or more microprocessors), as firmware, or asvirtually any combination thereof, and that designing the circuitryand/or writing the code for the software and or firmware would be wellwithin the skill of one of skill in the art in light of this disclosure.In addition, those skilled in the art will appreciate that themechanisms of the subject matter described herein are capable of beingdistributed as one or more program products in a variety of forms, andthat an illustrative form of the subject matter described herein appliesregardless of the particular type of signal bearing medium used toactually carry out the distribution. Examples of a signal bearing mediuminclude, but are not limited to, the following: a recordable type mediumsuch as a floppy disk, a hard disk drive, a Compact Disc (CD), a DigitalVideo Disk (DVD), a digital tape, a computer memory, etc.; and atransmission type medium such as a digital and/or an analogcommunication medium (e.g., a fiber optic cable, a waveguide, a wiredcommunications link, a wireless communication link (e.g., transmitter,receiver, transmission logic, reception logic, etc.), etc.).

In some instances, one or more elements may be described using theexpression “coupled” and “connected” along with their derivatives. Itshould be understood that these terms are not intended as synonyms foreach other. For example, some aspects may be described using the term“connected” to indicate that two or more elements are in direct physicalor electrical contact with each other. In another example, some aspectsmay be described using the term “coupled” to indicate that two or moreelements are in direct physical or electrical contact. The term“coupled,” however, also may mean that two or more elements are not indirect contact with each other, but yet still co-operate or interactwith each other. It is to be understood that depicted architectures ofdifferent components contained within, or connected with, differentother components are merely examples, and that in fact many otherarchitectures may be implemented which achieve the same functionality.In a conceptual sense, any arrangement of components to achieve the samefunctionality is effectively “associated” such that the desiredfunctionality is achieved. Hence, any two components herein combined toachieve a particular functionality can be seen as “associated with” eachother such that the desired functionality is achieved, irrespective ofarchitectures or intermedial components. Likewise, any two components soassociated also can be viewed as being “operably connected,” or“operably coupled,” to each other to achieve the desired functionality,and any two components capable of being so associated also can be viewedas being “operably couplable,” to each other to achieve the desiredfunctionality. Specific examples of operably couplable include but arenot limited to physically mateable and/or physically interactingcomponents, and/or wirelessly interactable, and/or wirelesslyinteracting components, and/or logically interacting, and/or logicallyinteractable components, and/or electrically interacting components,and/or electrically interactable components, and/or opticallyinteracting components, and/or optically interactable components.

In other instances, one or more components may be referred to herein as“configured to,” “configurable to,” “operable/operative to,”“adapted/adaptable,” “able to,” “conformable/conformed to,” etc. Thoseskilled in the art will recognize that “configured to” can generallyencompass active-state components and/or inactive-state componentsand/or standby-state components, unless context requires otherwise.

While particular aspects of the present disclosure have been shown anddescribed, it will be apparent to those skilled in the art that, basedupon the teachings herein, changes and modifications may be made withoutdeparting from the subject matter described herein and its broaderaspects and, therefore, the appended claims are to encompass withintheir scope all such changes and modifications as are within the truescope of the subject matter described herein. It will be understood bythose within the art that, in general, terms used herein, and especiallyin the appended claims (e.g., bodies of the appended claims) aregenerally intended as “open” terms (e.g., the term “including” should beinterpreted as “including but not limited to,” the term “having” shouldbe interpreted as “having at least,” the term “includes” should beinterpreted as “includes but is not limited to,” etc.). It will befurther understood by those within the art that if a specific number ofan introduced claim recitation is intended, such an intent will beexplicitly recited in the claim, and in the absence of such recitationno such intent is present. For example, as an aid to understanding, thefollowing appended claims may contain usage of the introductory phrases“at least one” and “one or more” to introduce claim recitations.However, the use of such phrases should not be construed to imply thatthe introduction of a claim recitation by the indefinite articles “a” or“an” limits any particular claim containing such introduced claimrecitation to claims containing only one such recitation, even when thesame claim includes the introductory phrases “one or more” or “at leastone” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an”should typically be interpreted to mean “at least one” or “one ormore”); the same holds true for the use of definite articles used tointroduce claim recitations.

In addition, even if a specific number of an introduced claim recitationis explicitly recited, those skilled in the art will recognize that suchrecitation should typically be interpreted to mean at least the recitednumber (e.g., the bare recitation of “two recitations,” without othermodifiers, typically means at least two recitations, or two or morerecitations). Furthermore, in those instances where a conventionanalogous to “at least one of A, B, and C, etc.” is used, in generalsuch a construction is intended in the sense one having skill in the artwould understand the convention (e.g., “a system having at least one ofA, B, and C” would include but not be limited to systems that have Aalone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). In those instances where aconvention analogous to “at least one of A, B, or C, etc.” is used, ingeneral such a construction is intended in the sense one having skill inthe art would understand the convention (e.g., “a system having at leastone of A, B, or C” would include but not be limited to systems that haveA alone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). It will be furtherunderstood by those within the art that typically a disjunctive wordand/or phrase presenting two or more alternative terms, whether in thedescription, claims, or drawings, should be understood to contemplatethe possibilities of including one of the terms, either of the terms, orboth terms unless context dictates otherwise. For example, the phrase “Aor B” will be typically understood to include the possibilities of “A”or “B” or “A and B.”

With respect to the appended claims, those skilled in the art willappreciate that recited operations therein may generally be performed inany order. Also, although various operational flows are presented in asequence(s), it should be understood that the various operations may beperformed in other orders than those which are illustrated, or may beperformed concurrently. Examples of such alternate orderings may includeoverlapping, interleaved, interrupted, reordered, incremental,preparatory, supplemental, simultaneous, reverse, or other variantorderings, unless context dictates otherwise. Furthermore, terms like“responsive to,” “related to,” or other past-tense adjectives aregenerally not intended to exclude such variants, unless context dictatesotherwise.

It is worthy to note that any reference to “one aspect,” “an aspect,”“one form,” or “a form” means that a particular feature, structure, orcharacteristic described in connection with the aspect is included in atleast one aspect. Thus, appearances of the phrases “in one aspect,” “inan aspect,” “in one form,” or “in an form” in various places throughoutthe specification are not necessarily all referring to the same aspect.Furthermore, the particular features, structures or characteristics maybe combined in any suitable manner in one or more aspects.

With respect to the use of substantially any plural and/or singularterms herein, those having skill in the art can translate from theplural to the singular and/or from the singular to the plural as isappropriate to the context and/or application. The varioussingular/plural permutations are not expressly set forth herein for sakeof clarity.

In certain cases, use of a system or method may occur in a territoryeven if components are located outside the territory. For example, in adistributed computing context, use of a distributed computing system mayoccur in a territory even though parts of the system may be locatedoutside of the territory (e.g., relay, server, processor, signal-bearingmedium, transmitting computer, receiving computer, etc. located outsidethe territory).

A sale of a system or method may likewise occur in a territory even ifcomponents of the system or method are located and/or used outside theterritory. Further, implementation of at least part of a system forperforming a method in one territory does not preclude use of the systemin another territory.

All of the above-mentioned U.S. patents, U.S. patent applicationpublications, U.S. patent applications, foreign patents, foreign patentapplications, non-patent publications referred to in this specificationand/or listed in any Application Data Sheet, or any other disclosurematerial are incorporated herein by reference, to the extent notinconsistent herewith. As such, and to the extent necessary, thedisclosure as explicitly set forth herein supersedes any conflictingmaterial incorporated herein by reference. Any material, or portionthereof, that is said to be incorporated by reference herein, but whichconflicts with existing definitions, statements, or other disclosurematerial set forth herein will only be incorporated to the extent thatno conflict arises between that incorporated material and the existingdisclosure material.

In summary, numerous benefits have been described which result fromemploying the concepts described herein. The foregoing description ofthe one or more forms has been presented for purposes of illustrationand description. It is not intended to be exhaustive or limiting to theprecise form disclosed. Modifications or variations are possible inlight of the above teachings. The one or more forms were chosen anddescribed in order to illustrate principles and practical application tothereby enable one of ordinary skill in the art to utilize the variousforms and with various modifications as are suited to the particular usecontemplated. It is intended that the claims submitted herewith definethe overall scope..

Various aspects of the subject matter described herein are set out inthe following numbered examples:

Example 1. An electrosurgical system comprising:

an RF current generator; a handle body; and

an end effector in mechanical communication with the handle body, theend effector comprising:

a first jaw comprising a first energy delivery surface in electricalcommunication with a first terminal of the RF current generator; and

a second jaw comprising a second energy delivery surface in electricalcommunication with a second terminal of the RF current generator,

wherein at least a portion of the first energy delivery surfacecomprises a patterned coating of an electrically non-conductingnon-stick material.

Example 2. The electrosurgical system of Example 1, wherein the firstenergy delivery surface has a first area and the at least portion of thefirst energy delivery surface comprising the patterned coating has asecond area.

Example 3. The electrosurgical system of Example 2, wherein a ratio ofthe second area to the first area is less than or equal to about 0.9.

Example 4. The electrosurgical system of Example 2, wherein a ratio ofthe second area to the first area is less than or equal to about 0.7.

Example 5. The electrosurgical system of Example 2, wherein a ratio ofthe second area to the first area is less than or equal to about 0.5.

Example 6. The electrosurgical system of any one or more of Example 1through Example 5, wherein the electrically non-conducting non-stickmaterial has a surface energy value between 1100 mJ/m² and 5 mJ/m².

Example 7. The electrosurgical system o of any one or more of Example 1through Example 5, wherein the electrically non-conducting non-stickmaterial has a surface energy value between 50 mJ/m² and 40 mJ/m².

Example 8. The electrosurgical system of any one or more of Example 1through Example 5, wherein the electrically non-conducting non-stickmaterial has a surface energy value between 40 mJ/m² and 12 mJ/m².

Example 9. An end effector for an electrosurgical device, the endeffector comprising:

a first jaw comprising a first energy delivery surface configured to bein electrical communication with a first terminal of an RF currentgenerator; and

a second jaw comprising a second energy delivery surface configured tobe in electrical communication with a second terminal of the RF currentgenerator,

wherein at least a portion of the first energy delivery surfacecomprises a patterned coating of an electrically non-conductingnon-stick material.

Example 10. The end effector of Example 9, wherein the first energydelivery surface has a first area and the at least portion of the firstenergy delivery surface comprising the patterned coating has a secondarea.

Example 11. The end effector of Example 10, wherein a ratio of thesecond area to the first area is less than or equal to about 0.8.

Example 12. The end effector of Example 10, wherein a ratio of thesecond area to the first area is less than or equal to about 0.7.

Example 13. The end effector of Example 10, wherein a ratio of thesecond area to the first area is less than or equal to about 0.5.

Example 14. The electrosurgical system of any one or more of Example 9through Example 13, wherein the electrically non-conducting non-stickmaterial has a surface energy value between 1100 mJ/m² and 5 mJ/m².

Example 15. The electrosurgical system of any one or more of Example 9through Example 13, wherein the electrically non-conducting non-stickmaterial has a surface energy value between 50 mJ/m² and 40 mJ/m².

Example 16. The electrosurgical system of any one or more of Example 9through Example 13, wherein the electrically non-conducting non-stickmaterial has a surface energy value between 40 mJ/m² and 12 mJ/m².

Example 17. The end effector of any one or more of Example 9 throughExample 16, wherein the patterned coating comprises the electricallynon-conducting non-stick material disposed within one or more recessedfeatures fabricated in the first energy delivery surface.

Example 18. The end effector of any one or more of Example 9 throughExample 17, wherein the one or more recessed features comprise one ormore circular features.

Example 19. The end effector of any one or more of Example 9 throughExample 18, wherein the one or more recessed features comprise one ormore rectangular features.

Example 20. The end effector of any one or more of Example 9 throughExample 19, wherein the one or more recessed features comprise one ormore linear features.

Example 21. The end effector of Example 20, wherein the one or morelinear features are disposed along or parallel to a longitudinal axis ofthe first energy delivery surface.

Example 22. The end effector of Example 20, wherein the one or morelinear features are disposed along or parallel to a transverse axis ofthe first energy delivery surface.

Example 23. The end effector of any one or more of Example 9 throughExample 22, wherein the patterned coating comprises the electricallynon-conducting non-stick material disposed on and in direct physicalcommunication with an exposed surface of the first energy deliverysurface.

Example 24. The end effector of Example 23, wherein the patternedcoating comprises a coating of the non-stick material lacking one ormore portions of the non-stick material.

Example 25. The end effector of Example 24, wherein the portions of thenon-stick material comprise one or more circular portions of thenon-stick material.

Example 26. The end effector of any one or more of Example 24 throughExample 25, wherein the portions of the non-stick material comprise oneor more rectangular portions of the non-stick material.

Example 27. The end effector of any one or more of Example 24 throughExample 26, wherein the portions of the non-stick material comprise oneor more elongated portions of the non-stick material.

Example 28. The end effector of any one or more of Example 21 throughExample 27, wherein at least a portion of the second energy deliverysurface comprises a second patterned coating of the electricallynon-conducting non-stick material that is disposed on and is in directphysical communication with an exposed surface of the second energydelivery surface; and

wherein the patterned coating is spatially offset with respect to thesecond patterned coating when the first jaw is brought into a proximateposition to the second jaw.

Example 29. The end effector of Example 28, wherein the second energydelivery surface has a third area and the at least portion of the secondenergy delivery surface comprising the second patterned coating has afourth area.

Example 30. The end effector of Example 29, wherein a ratio of thefourth area to the third area is less than or equal to about 0.8.

Example 31. The end effector of Example 29, wherein a ratio of thefourth area to the third area is less than or equal to about 0.7.

Example 32. The end effector of Example 29, wherein a ratio of thefourth area to the third area is less than or equal to about 0.6.

Example 33. The end effector of any one or more of Example 28 throughExample 32, wherein the patterned coating comprises a coating of thenon-stick material lacking one or more elongated portions of thenon-stick material and the second patterned coating comprises a coatingof the non-stick material lacking one or more second elongated portionsof the non-stick material.

1.-33. (canceled)
 34. An electrosurgical system comprising: an RFcurrent generator; a handle body; and an end effector in mechanicalcommunication with the handle body, the end effector comprising: a firstjaw comprising a first energy delivery surface having a total surfacearea in electrical communication with a first terminal of the RF currentgenerator; and a second jaw comprising a second energy delivery surfacein electrical communication with a second terminal of the RF currentgenerator, wherein a patterned coating of an electrically non-conductingnon-stick material comprises a second surface area disposed on the totalsurface area, and wherein a ratio of the second surface area to thetotal surface area ranges between 50% and 80%.
 35. The electrosurgicalsystem of claim 34, wherein the electrically non-conducting non-stickmaterial has a surface energy value between 1100 mJ/m2 and 5 mJ/m2. 36.The electrosurgical system of claim 34, wherein the electricallynon-conducting non-stick material has a surface energy value between 50mJ/m2 and 40 mJ/m2.
 37. The electrosurgical system of claim 34, whereinthe electrically non-conducting non-stick material has a surface energyvalue between 40 mJ/m2 and 12 mJ/m2.
 38. An end effector for anelectrosurgical device, the end effector comprising: a first jawcomprising a first energy delivery surface having a total surface areaand configured to be in electrical communication with a first terminalof an RF current generator; and a second jaw comprising a second energydelivery surface configured to be in electrical communication with asecond terminal of the RF current generator, wherein at least a portionof the first energy delivery surface comprises a patterned coating of anelectrically non-conducting non-stick material, wherein a patternedcoating of an electrically non-conducting non-stick material comprises asecond surface area disposed on the total surface area, and wherein aratio of the second surface area to the total surface area rangesbetween 50% and 80%.
 39. The end effector of claim 38, wherein theelectrically non-conducting non-stick material has a surface energyvalue between 1100 mJ/m2 and 5 mJ/m2.
 40. The end effector of claim 38,wherein the electrically non-conducting non-stick material has a surfaceenergy value between 50 mJ/m2 and 40 mJ/m2.
 41. The end effector ofclaim 38 wherein the electrically non-conducting non-stick material hasa surface energy value between 40 mJ/m2 and 12 mJ/m2.
 42. The endeffector of claim 38, wherein the patterned coating comprises theelectrically non-conducting non-stick material disposed within arecessed feature fabricated in the first energy delivery surface. 43.The end effector of claim 42, wherein the recessed feature comprises acircular feature.
 44. The end effector of claim 42, wherein the recessedfeature comprises a rectangular feature.
 45. The end effector of claim42, wherein the recessed feature comprises a linear feature.
 46. The endeffector of claim 45, wherein the linear feature is disposed along orparallel to a longitudinal axis of the first energy delivery surface.47. The end effector of claim 45, wherein the linear feature is disposedalong or parallel to a transverse axis of the first energy deliverysurface.
 48. The end effector of claim 38, wherein the patterned coatingcomprises the electrically non-conducting non-stick material disposed onand in direct physical communication with an exposed surface of thefirst energy delivery surface.
 49. The end effector of claim 48, whereinthe patterned coating comprises a coating of the electricallynon-conducting non-stick material lacking a portion of the electricallynon-conducting non-stick material.
 50. The end effector of claim 49,wherein the portion of the electrically non-conducting non-stickmaterial comprises a circular portion of the electrically non-conductingnon-stick material.
 51. The end effector of claim 49, wherein theportion of the non-stick material comprises a rectangular portion of theelectrically non-conducting non-stick material.
 52. The end effector ofclaim 49, wherein the portion of the non-stick material comprises anelongated portion of the electrically non-conducting non-stick material.53. The end effector of claim 49, wherein the second energy deliverysurface, having a second total area, comprises a second patternedcoating of the electrically non-conducting non-stick material that isdisposed on and is in direct physical communication with an exposedsurface of the second energy delivery surface, wherein the secondpatterned coating comprises a third surface area, and wherein a ratio ofthe third surface area to the second total surface area ranges between50% and 80%.